Lock our ansible version down to our own fork

This commit installs a version of ansible that we have curated with
specific commits.  Because ansible cannot be installed via a
requirements.txt file, a script was added to make this easier. As our
fork has the 'gather_facts: force' option, also enable this.
Add ansible 1.7.2-bbg to the requirements file

Thanks to @paulczar I am now adding our ansible fork to the
requirements file via tarball vs source. This is a much cleaner way
to go.
Merge pull request #677 from blueboxgroup/install-ansible

Lock our ansible version down to our own fork