Minor JS refactoring
Pulls date formatting into fieldHelpers.js
Reorders functions in inlineEditForm.js
Add proper date support to form_extras tags and inlineEditForm.js
Fixes #886
Use field.choices in form_extra.py to create dropdowns for fields
Loosen up identifier regex, allowing variables not named after models

Whitelisting the model part of model.field was a bit of a misnomer, since
it whitelisted the template variable name, not the actual model class it
represented.

Identifiers still need to be of the form "model.field" though, in order to
access the field metadata on the model class
Merge pull request #894 from maurizi/inlineEditChanges

Inline edit changes