OutputVideo: refactoring - rename local variable
AudioFrameDesc: add setSampleFormat from name
AudioDesc: add setAudioParameters from an audioFrameDesc
VideoFrame: add setParameters from a profileDesc

Update avTranscoder swig file.
AudioFrame: add setParameters from a profileDesc
Video/AudioFrame: refactoring - reorder includes
StreamTranscoder: set outputVideoFrameDesc with setParameters

* Instead of setPixel.
* Suppress comments.
StreamTranscoder: set outputAudioFrameDesc with setParameters

* If a subStream is selected, set channels of the frameDesc used to
instanciate _sourceBuffer.
* Add todo.
Audio profile: avProfileSampleRate is not required

If no sample rate is indicated in the profile, the output file will have
the same sample rate as the input file.
Audio profile: avProfileChannel is not required

If no number of channel is indicated in the profile, the output file
will have the same number of channels as the input file.
Transcoder: refactoring - group switch cases
DataStreamDesc: rename to DataStream

Rename the file.
InputAudio: refactoring readNextFrame - no need to update offset if big endian
InputAudio: check subStream in readNextFrame

If the subStream doesn't exist, raise an exception.
InputAudio: refactoring - rename local variable

Rename nbChannels to nbSubStreams.
Merge pull request #32 from cchampet/dev_subStreams

Refactoring & minor updates