TurboGears 2.5.0 deprecations removal

[amol-]

Version 2.5.0 will remove all deprecated features that have been around for multiple versions. It's a good idea to start using version 2.4 to gather the DeprecationWarning messages and get rid of them before 2.5 is released.

The only Deprecated compatibility layer that will remain in place is AppConfig, the AppConfig class will still be in place until 2.6 as it's recognised that migrating from it to newer configurators introduced in 2.4 requires a long effort and it has only been recently deprecated.