work in progress
remove explicit form_url param and generalize method
add session context endpoint and simplify session access apis
basic support for session resume in cloudcare

- adds a bunch of backbone models and views for sessions
- splits playing the form into two methods so the latter can be shared
- UI could use some work
pass session name (including case name if available) to touchforms
dialog confirm change
whitespace and remove dead comment
basic UI for deleting sessions, move session list to top level
dead code and js syntax fixes
sync session list on form submissions
add app id to sessions
properly set the app in the view when playing a session