add example for filtering options in forms

fix validation type matches.

Using sorted list field not handled (and crash) in process_ajax_references

add example of disabled field to docs

add mongoengine ReferenceField filter

Added hybrid properties filters support

add json support to SQLA backend

Add default type formatters for Enum

Fix typo

List row actions

Allow flipping mapbox coordinates to/from db

remove unnecessary indention in form.py convert

Fixed bugs