Add suitable docstrings to the module, classes and functions

[Ankit Aggarwal]

Please refer these links while constructing the suitable docstrings.

• https://www.python.org/dev/peps/pep-0257/
• http://stackoverflow.com/questions/2557110/what-to-put-in-a-python-module-docstring
• http://sphinxcontrib-napoleon.readthedocs.io/en/latest/example_google.html

Any suggestions are welcome. Thanks.

[Tushar Kataria]

I'll try to work on this.Can you please explain the purpose/use of the function f(..) and cnn(..) inpycnn.py.

[Ankit Aggarwal]

Thanks @lostwarrior404. I appreciate your help.

cnn function is the approximate sigmoidal kernel function for this neural network.

f(x, t, ...) computes the derivative of x at t.

[Iraquitan Cordeiro Filho]

Adde PR#30 for this issue.

[Ankit Aggarwal]

Excellent work @iraquitan, but @lostwarrior404 mentioned that he is working on this issue. I hope he didn't start working on it.
In the future, please comment on the issue that your working on to avoid any duplication. Thank you for your contribution.

@lostwarrior404, shall we go ahead with this? I hope you didn't start working on this yet.

[Tushar Kataria]

Please go ahead with it.Open source software is about community not about a single person.And @iraquitan has done a much better job than me.

[Ankit Aggarwal]

@lostwarrior404, thanks for your good open source spirit.
Your contribution is appreciated. @iraquitan, please go ahead with this issue.

[Iraquitan Cordeiro Filho]

Ok, I should've commented here before working. I'll do that next time. Thanks for comprehension @lostwarrior404 and @ankitaggarwal011.