1.0.0.51

Membership: added Delete field to mark a membership for deletion.
Membership: added Amount Remaining field to show any amount remaining that is due.
Membership Levels and Renewals: showing Last Sent Date under heading.
Organization: added membership renewal subject, message and due date fields for users to customize the membership renewal message that is sent.
Organization: added Last Membership Renewal Reminder Sent field to show when reminders were last sent to members to renew.
Payment Types: added Credit option for any amount being discounted, written off or subtracted.