Move display_filters.html into correct directory
Return geoRevHash with plot API response

This was implemented previously, but it looks like it may have gotten
lost in a refactor. I have also taken the opportunity to standardize the
dictionary key name. The geo rev is always referred to as "geoRevHash"
Merge pull request #1228 from jwalgran/topic/api-plot-update-returns-georev

Return geoRevHash with plot API response
Don't send UDFC data when perm not there
Update UDF documentation/debug output
Change the way collection udfs save

Only cast to python when you are instantiating objects, not saving. save_with_user was calling collection_fields() which cleans values and casts to python. These can't save properly.

Don't save collection udfs when they haven't changed. This is important for permissions, since UDFModels call this method on every save, even saves by users that aren't permitted to change UDF values.