Patch for migration of hours balance from accounts to members.

All of the following changes were made to support the migration of
hours balances from accounts to members. Changes in include the
following:
 - Changing of all MESS user templates that reference account hours
   balance
 - Creation of reports that show member hours balances
 - Python script that migrates account hours to member hours
 - Creation of Member Hours Balance form in reports
 - etc.
Re-added "Over Balance" report which was removed from Accounts report
list by mistake.
Fixed bug where recur rule was not being saved properly when task was
saved for first time
Removed After-Hours Sale purchase option from trans_summary report
Removed last paragraph about freezing accounts from shift reminder
email.

Jane tells me this is no longer standard practice.
Initial commit for new member_card property in the Member model.

We now have member cards, and the 12 digit UPCs that come with member
cards will be connected to their member accounts. This commit adds
the necessary "member_card" field to the Member class to make this
happen.
Added AutherChecker as an Authentication Backend.

Checks user/password in auther.
If not successful, calls default Django authentication backend.
Host, etc are configured in settings.py
Merge branch 'auther' of github.com:mariposacoop/mess into auther