Added support to the new bob.extension global config. Added the variables facenet_modelpath and drgan_modelpath to the bobrc

added the DR-GAN encoder as a bob.bio.base.extractor

See merge request !3

added the DR-GAN encoder as a bob.bio.base.extractor

[DR-GAN] removed the dependency to bob.bio.base.extractor

[DR-GAN] added test for DR-GAN

Organized the download mechanism

Added some documentation

Update FaceNet.py -- Add an example preprocessor

See merge request !2

Add Facenet

See merge request !1