Added:
 - LayerCNN class - initial convolution version for SSB.
 - Simplest test for convolution. Require mnist in HDF to run.
 - legend_on flag for Graph

Current limitation:
 - activation for CNN layers. It works with all types except MaxOut.
 - not fully tested
 - works with squares images, square kernels and perform square pooling

Available options:
 - Sparsity for kernel (may be buggy)
 - Dropout reg.
 - possible to choose: Optimized (cuda-convnet) or Theano internal calculation
 - Flexible conv and pooling strides
 - It is possible to enable/disable pooling

Changed:
 - Activation function's signature: from now za argument it takes z (now W, X, B as it was before). Now W x X + B - calculates in layers.