Updating to use new release format (wheels)

Fetch script now looks for .whl files, downloads them into a "wheels"
directory.
Changed name of wheel storage directory

to "wheelhouse"
Updating wheel-fetching and installation
Merge branch 'master' of github.com:numenta/nupic.regression into fetch-wheels
Install wheels locally before testing
Rearranging dependencies in .travis
Updating pip so it can get wheels
It's called wheel, not wheels, dummy
Merge pull request #17 from rhyolight/fetch-wheels

Building NuPIC with wheels.