Issue: SPR-13747

This change refines the logic of "mapping" content negotiation
strategies with regards to how to handle cases where no mapping is
found.

The request parameter strategy now treats request parameter values that
do not match any mapped media type as 406 errors.

The path extension strategy provides a new flag called
"ignoreUnknownExtensions" (true by default) that when set to false also
results in a 406. The same flag is also exposed through the
ContentNegotiationManagerFactoryBean and the MVC Java config.

Issue: SPR-10170

Issue: SPR-8410, SPR-8417, SPR-8418,SPR-8416, SPR-8419,SPR-7722

Introduced ContentNeogtiationStrategy for resolving the requested
media types from an incoming request. The available implementations
are based on path extension, request parameter, 'Accept' header,
and a fixed default content type. The logic for these implementations
is based on equivalent options, previously available only in the
ContentNegotiatingViewResolver.

Also in this commit is ContentNegotiationManager, the central class to
use when configuring content negotiation options. It accepts one or
more ContentNeogtiationStrategy instances and delegates to them.

The ContentNeogiationManager can now be used to configure the
following classes:

- RequestMappingHandlerMappingm
- RequestMappingHandlerAdapter
- ExceptionHandlerExceptionResolver
- ContentNegotiatingViewResolver

Issue: SPR-8410, SPR-8417, SPR-8418,SPR-8416, SPR-8419,SPR-7722