Switch to using bundletester for execution of functional tests,
leveraging tox to build out test virtualenvs.
Rename amulet tests inline with gate-* and dfs-* naming standards.
Update README to refer to functional testing section of the charm
The new release of charm-tools no longer ships the charm
command; update minimum version requirement and switch
to using charm-proof instead, unblocking current pep8
failures across all charms.
Also pin the version of requests to 2.6.0 until theblues
(indirect dependency of charm-tools) sort out its