OptionLoader: getPixelFormats, manage backward compatibility
OptionLoader: refactoring

* Backward compatibility: always the old version in first.
* getPixelFormats: no spaces between the name of the function and its
list of parameters.
Merge branch 'master' of https://github.com/MarcAntoine-Arnaud/avTranscoder
Merge pull request #12 from cchampet/master

Backward compatibility