Working towards Windows build

This PR is for tracking the latest work on #103 and #134. It is not ready to merge.

Since the work is to make `nupic.core` compiles under Windows, I've set up the CI for VC and MinGW at https://ci.appveyor.com/project/utensil/nupic-core , for details please refer to #134 .

@rcrowder Let's continue the discussion here.