Added experimental support for animated GIFs

- Moved AviarySDK from global namespace to "AviarySDKDLL" alias. If you
want to use it add `external alias AviarySDKDLL; using
AviarySDKDLL::AviarySDK` to your files
- Added ImageTools library
- Changed helper methods to use extended images
! Known Bug: animated GIFs use a lot of memory which might cause
application crashes. Todo: think of an workaround.
(Commit related to #53)