Added support for sqlalchemy_enum34 filters

New ARRAY type for sqlalchemy

In 1.1.0 [1] SqlAlchemy changed base type for ARRAY type.
This is causing flask-admin to skip ARRAY fields due to unknown type.
Now, the base type for ARRAY type is sqlalchemy.sql.sqltypes.ARRAY

See: http://docs.sqlalchemy.org/en/latest/changelog/changelog_11.html#change-1.1.0b1-sql

Use Google Places for map box search

Revert PR #1231

Fix regression with late-evaluation relationships no longer working with filters

Regression was introduced in 47080aeb (PR #1348) where `is_hybrid_property` was changed to support remote hybrid properties. When lambdas were encountered in the iteration they were passed as-is to the function `get_hybrid_properties`, which in turn threw the exception `sqlalchemy.exc.NoInspectionAvailable: No inspection system is available for object of type <class 'function'>`.

Test has been updated to ensure that flask-admin will continue to support lambdas as a relationship’s first argument.

Also:

* Upgrades `leaflet` to 1.0.0 final.
* Removes `leaflet.search` which was not working reliably (not even in their own demos...)
* Map uses full width of form container by default
* Ability to use a new app configuration key `GOOGLE_MAPS_API_KEY`. [This allows for increased daily quotas and ability to track usage](https://developers.google.com/maps/documentation/javascript/get-api-key). Note that this key must have Google Places API enable. See link.

Add desc as a function parameter to sort_url

on_form_prefill() should be executed when form validation fail.

Fix bad call `super()` in `BaseSQLAFilter.apply`

Mistake on my part. See discussion in #1341.

Fixes #1341

Added sorting, labeling and visibility configuration to file admin columns

Extract a method for calculating inline model keys

Support association proxies in path when determining hybrid property

1) Added support for dealing with association proxies when determining if field path is a hybrid property.
2) Restored support for filters using column values (not just their names).

Fixes #1339 and adds python 3 support to the example

Fix CSRF for production deployments

Added support for remote hybrid properties filters

To provide a way to custom the inline model keys
in the case of two same inline model class.

Fix #1347

Current SecureForm implementation generates CSRF secret using
`os.urandom()` every time when application start up. CSRF secret is used
to calculate csrf_token check value, so if someone would use a command
similar to

    gunicorn --workers=8 app

to run his flask-admin app on production then most form submissions
would silently fail (silently - as for now, it is probably another one
bug).

Instead of custom `os.urandom()` logic the `app.secret_key` value should
be used to produce CSRF token values.

Added support for sqla association proxy in model view.

allow user to set  flag "ignore_hidden"

Fix geoa.GeoJSONField