Improved action filter and action execution flow by supporting installing action filters at controller, module and application levels

Added support to allow an event handler to be inserted at the beginning of the existing event handler list

Fixes #2955: Changed the signature of ActiveQuery constructors and `ActiveRecord::createQuery()` to simplify customizing ActiveQuery classes

Fixes #2912: Relative view files will be looked for under the directory containing the view currently being rendered

so information about changed values is available in `afterSave`-event.

fixes #2892