Wrapping Keypoint Dataset

[cotemyriam]

Pierre-Luc et Vincent

The tasks included in this ticket are :
-Add keypoint data to SFEW's wrapper class
-Wrap the Flickr dataset
-Wrap the multiPIE dataset
-Wrap the BioID dataset
-Wrap the LFPW dataset
-Wrap the Caltech 10000 Web Faces dataset
-Wrap the AR Face dataset (Previously done by Vincent)