Removing simple_main.cpp

After figuring that the GPU hardware in one of the laptops was incapable
of using the Unified Memory in CUDA. After compilation of the original
main program on Amazon GPU cluster can get rid of the test case.
Modified the call to the CUDA Kernel to a pointer to a constructed NN.
Have the main with a cu CUDA file extension.
Fixed a typo in the naming of a default switch statement.
A number of fixes for the GPU implementation of the NN class.

Fixed the include for the Amazon host.

Removed the sigmoid function call in the CUDA Kernel and changed the
type of data from a float to accept a NN for the Evaluate CUDA Kernel.
Removal of the cpp version of main.