#184 Review PR

This PR is created for initial reviewing of the changes of #184 because #184 includes many external changes and hard to review.
It's better to keep README brief and clear, so these few paragraphs could be put somewhere in wiki and linked. Possiblly Development Tips.

And some of the description will become outdated when this PR is merged, e.g. the mention of https://ci.appveyor.com/project/rcrowder/nupic-core

`$NUPIC_CORE/build/temp/lib` should not be guided to, because they are temporal.