Cnn (#22)

* Created cnn module

+Added current rst for cnn
+Added current images I have made
*Still need to make 9 more images
*Still need to link images in rst

* Added remaining images

+Added images to _img folder
*Still need to put figures in the rst

* Added figures to rst

* Updated cnn.rst

+Add bold terms
+Fixed image link

* Updated cnn.rst

+Added references section

Author: b-sherman