CMake avplay: do not build the app if OpenGL or GLUT are not found

* Print a warning if avplay app can't be built.
* Allow the user to build avTranscoder library even if dependencies of
this app are not found.
* fix #94
Merge pull request #98 from cchampet/build_avplay_optionnal

CMake avplay: do not build the app if OpenGL or GLUT are not found
ProgressListener: add IProgress class

* Base class of all possible Progress.
* ProgressListener inherits this base class.
* Add documentation.
* Swig: add feature "director" to the base class.
ProgressListener: rename ProgressListener to ConsoleProgress

the class implements the IProgress, to display a progress bar in
console.
ProgressListener: add NoDisplayProgress class

* Manage cases when we need an IProgress but don't care of a progress
bar.
* Use it in avMeta app: we want the file infos, but don't care of the
progress bar.
ProgressListener: separate interface from implementation

* Create ProgressListener.cpp.
* Add include to iostream in Transcoder.
Add progress folder

* Contains all files related to the progress.
* Also contains corresponding swig interface file.
Progress: split into one class per file

* 3 classes / files: IProgress, ConsoleProgress, NoDisplayProgress.
* Add a cpp file just for ConsoleProgress (the implementation is more
'complicated' than the others).
Merge pull request #100 from cchampet/dev_Progress_fix_java_binding

ProgressListener: clean
Merge branch 'master' of https://github.com/avTranscoder/avTranscoder into dev_common_naming_nomenclature

Conflicts:
	app/avMeta/avMeta.cpp
	app/avTranscoder/avTranscoder.cpp
	app/avplay/AvReader.hpp
	app/genericProcessor/genericProcessor.cpp
	src/AvTranscoder/file/InputFile.hpp
	src/AvTranscoder/progress/progress.i