Make CounterField increment by specified value instead of 1
Review Request #3948 — Created March 8, 2013 and submitted
Add support for CounterField's increment and decrement functions to increment/decrement by a specified value rather than 1. The values still default to 1, so existing functionality continues to work. Note: This functionality is required for the issue counts to be calculated. Please see review 3949
Tested with creating review requests, adding reviews with multiple issues and verifying the counts are correct.