Add documentation for "persistent filter" to get_query

This documents the tip in this issue (for only SQLA): https://github.com/mrjoes/flask-admin/issues/169

Added _search method for mongoengine and pymongo backends for easier override

Fix sorting and searching for relation objects

add menu item settings for AdminIndexView

Fix sorting on related columns

add `menu_class_name`, `menu_icon_type` and `menu_icon_value` for
AdminIndexView

Fix display of initial value in editable list view

Currently, the editable list view is not setting the default value correctly.

With this change, if the value is "Active", when the user first clicks the editable field it will automatically select "Active" in the dropdown.

Simplify delete_form field rendering

add forgotten csrf_token._value() to bootstrap3

Allow easier overriding of editable list view

fix index_view csrf value rendering

add gettext to file-admin

Fix persian translation

(No translation changed, only update .po file)

Fix delete_view CSRF vulnerability

Add editable list view

Improve quickstart documentation

Fix SQLAlchemy default sort order when column name is ambiguous.

Instead of sorting on the raw column name, sort on the attribute we found. This fixes sorting for column names that are ambiguous due to table joins.

Add notes about _handle_view, index_view, edit_view, and create_view.