fix errors on form details page when form references an invalid case

the form details page used to get case ids from a view that emitted all
form ids for known cases, so this problem never came up.

Now that we look at the case ids referenced in the form, if a form has
an incorrect case id or a case was deleted due to a user being deleted
then this problem occurs.

Displaying something instead of nothing for this case is good.
Merge pull request #37 from dimagi/case-59312

fix errors on form details page when form references an invalid case (Case:59312)
Merge pull request #36 from dimagi/case-59262

form display fixes
wip, need to remove printouts.
realizing that one needs to save the doc before put_attachment, ugh
Ignore distutils droppings
Add some mandatory and semi-mandatory dependencies
Add mocked up settings
Add travis config
Explicitly provide settings module to test invocation
Switch to README.md to have a CI badge
manually install coverage
Show traceback on errors
Set lower bound on dimagi-utils
Add couchdb
Merge pull request #38 from kennknowles/travis-ci

Travis CI
Version 0.1.0
Add basic travis config for django-ish installable app
Add testing settings.py
Add basic setup.py
Merge pull request #39 from kennknowles/master

Version 0.1.0