Fix for issue 3385135 "source code cleanup" engine part

- remove commented code
- remove code under #if 0
- remove macro FILE_LOWER_CASE as it is not used
- remove macro #if 1
- remove TIMESCALE_BUG macro, and all code under this macro as it is not used
- remove following unused functions:
    * M4MCS_getExifInfo
    * M4MCS_registerAudioEncoderExtended
    * M4MCS_registerVideoDecoderExtended
    * M4MCS_registerAudioDecoderExtended
    * M4MCS_registerVideoEncoderExtended

Change-Id: I8e2916d956af6d381ae1962fedc61a8b48f60ce2