Support for MLP, CNN, and RBM

Implemented support for three different neural network types:

• Multilayer Perceptron
• Convolutional Neural Network
• Deep Belief Network

MLP implementation

Finished first milestone of implementing multilayer perceptron network, where all neurons in each pair of neighboring layers are fully interconnected. Both serial (CPU) and parallel (GPU) implementations are supported. Network is configurable via command-line options. A set of testing scripts is attached along with the code.