Renamed `attributeName` and `className` to `targetAttribute` and `targetClass` for `UniqueValidator` and `ExistValidator`.
Refactored UniqueValidator and ExistValidator.

Fixes #1579: throw exception when the given AR relation name does not match in a case sensitive manner.
Renamed `ActiveRecord::getPopulatedRelations()` to `getRelatedRecords()`

also fixed count behavior according to limit and offset.
fixes #1458

fixed #1021

issue #1313

Method file unit tests improved.

Mongo GridFS AR added as draft.

Moved file and path related methods from StringHelper to FileHelper, renamed StringHelper byte methods not to be misused as string methods

Logging and profiling for Mongo Query added.