OptionLoader: getPixelFormats and getSampleFormats are static

You can get the list of pixel formats and sample formats without an
instance of OptionLoader.

Conflicts:

	src/AvTranscoder/OptionLoader.cpp
	src/AvTranscoder/OptionLoader.hpp
OutputEssence: raise exception in setup instead of return false

OutputVideo and OutputAudio: raise runtime_error if "could not allocate"
or "could not open" video / audio codec.
Audio profile: remove channel layout requirement

Fix: the channel layout is not required by FFMPEG when open audio codec context. So an audio profile has not to set this value.
OutputAudio: remove sample rate and channel checks of profile
OutputVideo: setProfile - refactoring
OutputAudio: setProfile - refactoring
Merge branch 'dev_OptionLoader' of https://github.com/cchampet/avTranscoder into cchampet-dev_OptionLoader

Conflicts:
	src/AvTranscoder/EssenceStream/OutputVideo.cpp
	src/AvTranscoder/OptionLoader.cpp
Merge branch 'cchampet-dev_OptionLoader'