*Validate and test the trained a wider range of TensorFlow models*
In this patch, a more mature code is provided:
- Dataset handling is factorized, we can now consider Mapillary or shape datasets
starting from a common Dataset basis
- Model handling is factorized, we can generate feature detection models or semantic
segmentation models, with common behaviors (basic layer creation, for instance)
- Some state-of-the-art models have been implemented (VGG, Inception)
- A base of code has been deployed for considering Keras API (the switch from TensorFlow
to Keras will be the object of a next minor release)