gcnn experiments reimplementation using Tensorflow

• We reimplemented Z2CNN, P4CNN, P4MCNN and P4CNN_RP for MNIST_ROT dataset.
• See my_gconv_exps/MNIST_ROT/models_tp.py for detailed usage.
• Also we add a chainer version P4MCNN model, which is not presented in the original paper. It performs better than the Z2CNN on mnist rotation dataset.