Defer @Conditional processing on @Configuration classes until the bean
definitions are loaded, rather than when the @Configuration class is
parsed. This provides better support for @Conditional implementations
that inspect bean definitions.

This commit also fixes some minor problems with original implementation
and replaces the ConditionalAnnotationHelper class with
ConditionEvaluator.

Issue: SPR-10534

Update ConfigurationClassUtils to only consider beans with @Bean
methods as 'lite' configuration candidates.

Prior to this commit all @Component beans were considered 'lite'
configuration candidates which could result in a large number of
ConfigurationClass instance being created that would ultimately be
ignored.

Issue: SPR-10609

Update AnnotationBeanNameGenerator to only use the value attribute of
a @Component meta-annotated annotation when it is a String.

Issue: SPR-10580

Add support for the EnvironmentAware interface with ImportSelector
and ImportBeanDefinitionRegistrar implementations.

Issue: SPR-10602

Test property placeholder with multiple locations and default values.

Issue: SPR-10619

 - cherry-pick of pull request #257, which originally applied to 3.2.x

Issue: SPR-10568

Issue: SPR-10546
(cherry picked from commit 6e4317eb)

Previously ConfigurationClassParser could override a nested
@Configuration without consideration of @Bean's defined in parent
classes.

This commit ensures that if the original ConfigurationClass contains
additional bean definitions it is processed again.

Issue: SPR-10546
(cherry picked from commit 940011e2)

Issue: SPR-10556

Issue: SPR-10559

Issue: SPR-10130

Issue: SPR-10307

Refactor ConfigurationClassEnhancer so that BeanFactory instances are
not held against CGLIB Callback objects. Enhanced @Configuration classes
now use the BeanFactoryAware interface in order to obtain a BeanFactory.

This change has the additional benefit that a static final field can
now be used to hold all Callback instances.

Issue: SPR-10307

Add DeferredImportSelector interface that can be used to select imports
after all @Configuration beans have been processed.

Introduce new @Conditional annotation that can be used to filter
which @Configuration classes or methods are loaded. @Conditional
can be used directly or as a meta-annotation. Condition implementations
are provided via the 'Condition' interface and are free to filter based
on any criteria available at the time that they run. The
ConditionalContext provides access to the BeanDefinitionRegistry,
Environment and ConfigurableListableBeanFactory along with a
ResourceLoader and ClassLoader.

The existing @Profile annotation has been refactored as a @Conditional
with the added benefit that it can now be used as a method level
annotation.

Add PropertySourcesPlaceholderConfigurer.getAppliedPropertySources() to
allow access to the PropertySources that were actually applied.

Issue: SPR-10545

Issue: SPR-8108

Removed spring-beans.dtd (the 1.x variant) and spring-oxm-1.5.xsd (pre-Spring-Framework variant), in order to raise the backwards compatibility limit a little bit at least. We'll keep supporting the 2.0 and 2.5 xsd versions for the time being, as well as spring-beans-2.0.dtd.

Removed the ref 'local' attribute in spring-beans-4.0.xsd since 'local' lost its differentiating role to a regular bean ref back in the 3.1 days when we started allowing for the same bean id to reappear in a different beans section of the same configuration file (with a different profile).

Issue: SPR-10437

Allow classes that are annotated with @Import to be considered as 'lite'
@Configuration candidates. Allows the AnnotationConfigApplicationContext
to directly register @Import beans even if they are not @Components.

Issue: SPR-10533

Exclude self @Component when parsing @ComponentScan annotations.

Issue: SPR-10531

Implementations of Spring's ImportSelector interface may
now implement any of the following *Aware interfaces and have their
respective methods called prior to #registerBeanDefinitions:

 - BeanFactoryAware
 - BeanClassLoaderAware
 - ResourceLoaderAware

Issue: SPR-10530

Add AnnotationConfigApplicationContext constructor allow use of a
custom DefaultListableBeanFactory.

Issue: SPR-10529

This allows for restoring a static MessageSourceResourceBundleLocator implementation, just implementing the interface at the new spi location introduced in HV 4.3 and preserved in 5.0.

Issue: SPR-8199

Issue: SPR-9644

This is largely derived from our existing Joda-Time support, with corresponding classes wherever possible.

Issue: SPR-9641

Issue: SPR-9639

Use LinkedHashMaps/Sets wherever exposed to users, and code tests defensively in terms of expected Map/Set ordering. Otherwise, there'll be runtime order differences between JDK 7 and JDK 8 due to internal HashMap/Set implementation differences.

Issue: SPR-9639

Issue: SPR-9641

In particular, avoid accidental usage of ASM for core JDK types - which will fail in case of a new bytecode version in the JDK, even if the application itself has been compiled with an earlier bytecode target.

Issue: SPR-10292

MethodValidationInterceptor autodetects Bean Validation 1.1's ExecutableValidator API now and uses it in favor of Hibernate Validator 4.2's native variant.
SpringConstraintValidatorFactory implements Bean Validation 1.1 "releaseInstance" method against new "destroyBean(Object)" method in AutowireCapableBeanFactory.
LocalValidatorFactoryBean adapts Spring-provided ParameterNameDiscoverer onto Bean Validation 1.1's ParameterNameProvider mechanism.
LocalValidatorFactoryBean reflectively adapts between the different ResourceBundleLocator SPI location in Hibernate Validator 4.2 versus 5.0.
LocalValidatorFactoryBean implements Bean Validation 1.1 "close" method.

Note: We still compile against Bean Validation 1.0 in order to not have to implement "forExecutables()" and "getParameterNameDiscoverer()" in LocalValidatorFactoryBean, SpringValidatorAdapter and CustomValidatorBean. Implementing those methods would imply references to Bean Validation 1.1 interfaces that break runtime compatibility with Bean Validation 1.0. Unfortunately, this means that all Bean Validation 1.1 API access has to be done via reflection.

Issue: SPR-8199

JSR-236 support, in particular adapting to JSR-236 Triggers and exposing additional metadata through ManagedTasks

This is built into ConcurrentTaskExecutor and ConcurrentTaskScheduler now, automatically detecting the JSR-236 ExecutorService variants and adapting to them.

Issue: SPR-8195