case type checks and update
replace couchforms update handler with python equivalent
fix test for python xml2json in couchforms

insignificant test change:
test is tightly coupled to an exception message
which used to be an erlang dump
and is now a lxml sytax error message

specifically added the text Invalid XML to the error message
so I could check for that rather than something more tightly coupled
update couchforms ref
improve response for downloading an xform with errors

Previously, when a download url for an xform within a working version of
an app is hit, it would 500. Now it 404s, with a body containing the
same errors that are displayed on the form-view page.

For downloading the xforms with a _build_, however, the behavior remains
unchanged.
raise a more intentional error when a bind is missing

fixes a test
Allow loading and saving of custom properties to careplan cases
Basic hello-world Google Analytics event tracking
enabling local testing of Google Analytics event tracking
event tracking for Edit Label
event tracking for Edit Pen
track app id when deploying
event tracking for Exchange publish
event tracking for Exchange view
event tracking for Exchange project downloads
store project ids when tracking publish events
separating event tracking for 'view' and 'view on exchange'
Merge branch 'master' into cp-custom-props
Merge branch 'master' into xform-error-404
Export properly formatted headers items