Profile: refactoring

* Function loadProfiles split in 2:
     * loadProfiles( const std::string& avProfilesPath = "" ), which
loads profiles. You can have a specific avProfilesPath, or use the path
contains in AVPROFILES (env variable).
     * loadProfile, which loads a single profile. The previous function
calls it for each profile.
* Function getFilesInDir: do not take "." and ".." as files.
Merge branch 'master' of https://github.com/MarcAntoine-Arnaud/avTranscoder
Profile: fix when AVPROFILES si empty
Merge pull request #19 from cchampet/master

Profile: can have a specific profile path