Fix bug 2073: comments were not displayed in notifications when the task was being closed. Bump version up to 2.15b3. Also, minor color change for task calendar.
Added in task 'delete', with significant code from Chris Davies. Adds in a new view for active tasks, a new column for pm_tasks that keeps track of whether a task is deleted or not, and adds in new delete pages. Includes upgrade scripts. There may be code that still needs to switch to using the pm_tasks_active view, but I caught all the obvious ones. Bump to version 2.13b2.