Filters to determine user role in an organization.

This feature allows for the ability to utilize template conditionals to
customize user functionality and/or behavior depending on their role
with a given organization.

The two main roles that a user can have with an organization are if the
user is an organization owner or an organization admin.
Merge pull request #54 from avelis/dev

Filters to determine user role in an organization.
Custom signals for organization changes.

Three signals are being added:
1. When a user is removed from an organization.
2. When a user is added to an organization.
3. When an organization changes ownership.

All three signals use the organization model as the sender. To better
capture change of ownership. The organization method `change_owner` was
created.

The philosophy behind this addition is to move responsibility of
changing ownership to the Organization model class versus the
OrganizationForm class.
Merge pull request #55 from avelis/dev

Custom signals for organization changes.
Remove permalink in favor of reverse

Permalink decorator has not been recommended for a long time.
Version bump