Implemented data augmentation

bob/learn/tensorflow/datashuffler/Base.py

bob/learn/tensorflow/datashuffler/DataAugmentation.py

bob/learn/tensorflow/datashuffler/Disk.py

bob/learn/tensorflow/datashuffler/ImageAugmentation.py

bob/learn/tensorflow/datashuffler/Memory.py

bob/learn/tensorflow/datashuffler/SiameseDisk.py

bob/learn/tensorflow/datashuffler/SiameseMemory.py

bob/learn/tensorflow/datashuffler/TripletDisk.py

bob/learn/tensorflow/datashuffler/TripletMemory.py

bob/learn/tensorflow/datashuffler/__init__.py

bob/learn/tensorflow/test/test_cnn.py

bob/learn/tensorflow/test/test_datashuffler_augmentation.py

bob/learn/tensorflow/test/test_dnn.py