NO BUG - Install RBTools 0.6

We were previously installing a pre-release of RBTools from Git. The
patches we were waiting on are now in RBTools 0.6. So, install the
released version from PyPI.

DONTBUILD (NPOTB)

--HG--
extra : rebase_source : 0c3c13c6e9ec24ae7ebcabe5b2e4fa64441b2332