Added submenu feature for bootstrap3 template

rediscli: prevent form submit when execute command

allow to use inherited form CharField or TextField fields for searching

clean() data in filters during get_list for pymongo

fix python 2.6 build failures

Fixed issue where 'size()' is still used.

Fixed issue where 'size()' is deprecated and still used and prevented making action on multi-choice items.

According to Postgres doc `DECIMAL` is equivalent to `NUMERIC`

DeleteRowAction label

Convert _LazyString to unicode before assign to _menu_categories

https://www.postgresql.org/docs/9.5/static/datatype-numeric.html

so flask_admin.contrib.sqla.filters.FilterConverter should treat this the same

Added CSS file for submenu support by bootstrap3

Fix DeprecationWarning raised by SQLAlchemy

Added missing requirement to TinyMongo example

Added TinyDB - TinyMongo Example.

Fixing bug with using multiple URL attributes

Updates README.rst with svg badges