MultipleField._is_select returns false if data is None

Currently,
ModelSelectField Multiple returns Error if field exists but has None value

This occur when creating a new item,
as the object has not been created on page load.

Modified to,
QuerySetSelectMultipleField._is_select returns False
when the items data selected from is None.

Added Test,
test_forms
  .WTFormsAppTestCase
    .test_modelselectfield_multiple_initalvalue_None
Field order could be lost

If "only" or "exclude" was used, the field order could be lost.
Add support to multiple databases. I tried keeping the API the same so that it is backwards compatible
Merge pull request #92 from IndiciumSRL/master

Add support to multiple databases with aliases
Update index.rst

Add some missed params to help.
Merge pull request #93 from mxck/patch-1

Update index.rst
Merge pull request #91 from wcdolphin/master

Supply a Flask JSON Encoder
Merge pull request #64 from lucasnemeth/wtf-order-fix

Field order could be lost
Merge pull request #60 from eventsage/master

Issue #59: MultipleField._is_select returns false if data is None
Added More Setup Information To The Documentation

Added information about the init_app() method in the docs to make it clear that this library is compatible with flask application factories. I almost did not use this project because I thought that this method was not supported.
Merge pull request #103 from JackStouffer/patch-1

Added More Setup Information To The Documentation
Simple README :punch:
version bump to 0.7.1
Added myself to AUTHORS