Fix DeprecationWarning

prevent validators from getting inserted twice

add form blocks to modal and fileadmin templates too

Add block form on edit and create templates

FileAdmin - alert user when upload fails due to file already existing

Do not disclose the file system full path

Update base.py

Fix & test for #988: column_filters in not compatible with babel.

Remove Flask-SQLAlchemy dependency

It should be noted that the declarative base still has to be configured
like this:

```python
MyBase:
    query = session.query_property()
```

Also decreased code duplication and removed unused imports.

For example, when uploading a file called "foo/bar.txt" twice, right now it shows the full directory (e.g., "File /your/system/directory/foo/bar.txt already exists"), instead of only showing "File foo/bar.txt already exists".

flask_admin/model/base.py:949: DeprecationWarning: Required is going away in WTForms 3.0, use DataRequired
(though in this case, I believe the correct choice is InputRequired, though that only matter if an object has id=0)

Added placeholder methods for calling functions before deletion

improve error message when resolve_ctx is missing

Use WTForms translations for (non-custom) validation errors

fix backwards compat issue with form rules + flask.ext.admin

lock flask-login to 0.2.11 until flask-security is fixed

Update base.py - Typing error

A simple typing error (which can create some misunderstanding if we read the code too fast).

fix build errors caused by pillow

CSV Documentation: fix max rows attribute name