add lazy_load_hooks.rb, which allows us to declare code that
should be run at some later time. For instance, this allows
us to defer requiring ActiveRecord::Base at boot time purely
to apply configuration. Instead, we register a hook that should
apply configuration once ActiveRecord::Base is loaded.

With these changes, brings down total boot time of a
new app to 300ms in production and 400ms in dev.

TODO: rename base_hook

For performance reasons, you can no longer call html_safe! on Strings. Instead, all Strings are always not html_safe?. Instead, you can get a SafeBuffer from a String by calling #html_safe, which will SafeBuffer.new(self).

  * Additionally, instead of doing concat("</form>".html_safe), you can do
    safe_concat("</form>"), which will skip both the flag set, and the flag
    check.
  * For the first pass, I converted virtually all #html_safe!s to #html_safe,
    and the tests pass. A further optimization would be to try to use
    #safe_concat as much as possible, reducing the performance impact if
    we know up front that a String is safe.

Unvendor'd MemCache-Client.  Now requires the MemCache Client gem as a dependency - Don't forget to gem bundle buys and girls

Run `rake bundle` before running tests.

The use of encryption prevents people from seeing any potentially secret values you've used.  It also supports and encrypt_and_sign model to prevent people from tampering with the bits and creating random junk that gets fed to

A motivated coder could use this to add an :encrypt=>true option to the cookie store.

Add config.preload_frameworks to load all frameworks at startup. Default to false so Rails autoloads itself as it's used.

Autoload ActiveSupport::Duration, Gzip, OptionMerger, OrderedHash, OrderedOptions, StringInquirer, TimeWithZone, and TimeZone also

Add ActiveSupport::MessageVerifier to aid users who need to store tamper-proof messages in cookies etc.

This is particularly useful for things like remember-me tokens in web applications and auto-unsubscribe links in emails.

Added ActiveSupport::BacktraceCleaner and Rails::BacktraceCleaner for cutting down on backtrace noise (inspired by the Thoughtbot Quiet Backtrace plugin) [DHH]

Signed-off-by: NDavid Heinemeier Hansson <david@loudthinking.com>