I had to pull the git urls out of the main requirements files because in order to install offline (--no-index), we need pip to install from local package archives rather than cloning repo.
The weird `cat` thing going on in the Makefile is because we need to install everything as part of a single `pip install` transaction. Without this, installing only requirements_git.txt will result in dependencies getting unintentionally updated.
These packages were getting silently updated, making vendoring these dependencies difficult.
This ensures that the expected versions of these packages are installed in the virtualenvs.
event emitter now caches to memcache where it is eventually picked up
by the stdout event emitter. This obviates event reassembly in the
callback receiver.
