Fixed _need_join check for SQLa filters.

Fix circular import between `babel` and `helpers`

 * `from flask.ext.admin.babel import gettext` returns the right one
 * I18n in `flash_errors` works correctly

Python 3 fix: FilterConverter sub-classing bug

Couldn't be instantiated more than once. This made it impossible to make a subclass of FilterConverter.

Fix misleading documentation

Remove unused code

FileAdmin Improvements

improve fileadmin flexibility by moving forms into functions, fix CSRF, and fix error messages on validation failure

Add AppEngine ModelViews for both DB and NDB.

Allow searching non-text SQLAlchemy column types

Add AppEngine ModelViews for both DB and NDB. Tested it works on flask_admin running on my local dev_appserver, and works much better than the built-in appengine admin site. More complex features still remain TBD (queries, as well as nested keys, and probably other obscure features)

Less whitespace for menu macro

Added field id to inline field parent divs

Make SQLAlchemy AJAX filters case insensitive

This is much less surprising to the user than case sensitive searches.

Add documentation for using menu icons