Duplicate build artifacts uploaded to S3

[oxtopus]

At the end of a Travis-CI build, the results are tarred, gzipped, and uploaded to S3. The filename is derived from the travis commit sha, which is shared for all four of the builds, accounting for python 2.6, python 2.7, gcc, and clang. We should derive the filename, or S3 key from the matrix of parameters that result in multiple builds.

For example:

nupic-linux64-$TRAVIS_COMMIT-$TRAVIS_PYTHON_VERSION-$CC.tar.gz

[rhyolight]

Obsolete