[bug 987801] peep-ify requirements

* creates a requirements.txt file with all the things that are in
  vendor/
* tweak fjord/manage.py so that it adds the vagrant virtualenv to
  sys.path if it's there and if not, adds vendor/ to site packages;
  this isn't a super great solution, but it's probably a good enough
  interim one while we're switching from one way of doing things to
  another
* changes vagrant_provision.sh to build a virtual environment--this
  speeds ./manage.py stuff up significantly
* adds sha checksums to compiled.txt requirements file

r?