Activation fixes

[tomfen]

• Fixed ActivationFunction() for bipolar steepened sigmoid, clipped linear, ramp
• Fixed derivatives for bipolar steepened sigmoid, clipped linear, ramp, ReLU, smoothReLU
• Fixed clone() method of clipped linear returning wrong class
• Added constructor for bip. steepened sigm. (there wasn't one)
• Fixed some comments and documentations
• Fixed activation test names
• Added test class for ramp
• Replaced checking Clone() value for null with checking if returned class is correct (this also checks for null) for all activation class tests
• Added better test cases for softmax, sin, log, relu
• fixed other minor bugs