Add Convolutional Layer

[cwcoogan]

We want to setup a convolutional layer that uses our Layer class inside the layers folder. This will need to use Filters instead of Neurons. Since we removed Neurons class, we will need to figure out where to store these. Most likely inside of the Layer class -- similar to how FullyConnectedLayer is currently handling it.

Needs to apply the convolutional function to each kernel ......... wi * xi * color channel