Emulated Frame-Generator fix

A fix was required to make Travis tests pass and to make tests properly behave in emulated frame-generation environment. Frame-Generator-Stub was changed from singleton to managed instances (one-instance-per-spec). Some tests were corrected to work as they should.

`S_REPEAT` event was added to player, which is fired when player is in the repeat mode and starts to play animation for second/third/fourth..... time