Image tests:

- Add detect test
- Updated EXTENSIONS that image can render
Merge branch 'feature/player_update' of https://github.com/alexschiller/modular-file-renderer into feature/test_image

Conflicts:
	mfr/image/handler.py
	mfr/image/test_image/test_handler.py
Fix detect test
Merge pull request #50 from alexschiller/feature/test_image_detect

Feature/test image detect