OptionLoader: add getAVPixelFormat and getAVSampleFormat

* getAVPixelFormat: get the enum value from the pixel format name.
* getAVSampleFormat: get the enum value from the sample format name.
OptionLoader: update doc
Profile: remove width and height

OuputVideo: width and height are set from the imageDesc. These informations are not in the profile.
Merge branch 'master' of https://github.com/avTranscoder/avTranscoder into dev_OptionLoader

Conflicts:
	src/AvTranscoder/OptionLoader.hpp
Merge pull request #25 from cchampet/dev_OptionLoader

dev OptionLoader