Adds basic member points tracking.

This commit adds some basic models to get member point tracking working.
Not much of the functionality is complete at this point.
Changes memberpoint model.

Changes the user in PointAccount to a OneToOneField so that each user
will only be able to have one point account. Also changes the reason in
PointTransaction from a TextField to a CharField.
Improves memberpoint admin interface.
Adds balance property to member point account.

Adds a property called balance to the PointAccount class that
automatically sums up all the transactions in that account and returns
the current balance of points for that account.
Adds member points to member list view.

Adds a column showing the balance of member points for each user on the
member list page.
Adds a created_by field to member points.

The created_by field is intended to keep track of what user is giving
out and removing member points from other users. There should probably
be some special user for when they are automatically deducted by the
system.
Merge branch 'develop' into feature/memberpoint

Conflicts:
	settings/base.py
Changes balance function to use aggregate.

Also removes unused files/lines as commented in the pull request.
Merge pull request #34 from justintconroy/feature/memberpoint

Adds support for member points