Doxygen broken

[utensil]

Doxygen files, initialized by @rhyolight in #21 , is now broken after #47 due to source structure change.

[utensil]

I'm personally interested in helping with documentation clean up or write up.

I have good knowledge about Doxygen and C++, along with some basic understanding of the code in nupic.core.

I can help a portion of the documentation when it is well planned and partitioned, I can also help with initializing it further.

B.T.W. I believe further documenting the source should be started after #41 , when the styles are settled.

[utensil]

I've fixed this issue in https://github.com/utensil/nupic.core/tree/issue-57-doxygen-broken . Please let me know if it's good for a PR .

[rhyolight]

Thanks.