Use a nib for task cells. WIP
Start work on an alternate table view cell class.
Add contexts & projects coloring in the TaskCell class.
Adjust the height of TaskCell's and enable line wrapping.

Also change TaskCell to ARC.
Remove FlexiTaskCell and associated classes.
Better align the priority and task labels in TaskCell.
Check date showing preference in the view controller instead of view.
Improve TaskCell appearance when in a grouped table view.

Height calculations still aren't quite right.
Merge branch 'feature/autoLayoutCells' into feature/splitIpadView

Task cell appearance is not 100% correct, and knowledge of the model
should be moved out of the TaskCell view class. But it works.

Conflicts:
	View Controllers/todo_txt_touch_iosViewController.m
Prefer readonly properties to bare getter methods, in the TaskBag protocol.
Prefer @property's and don't re-declare protocol methods in TaskBagImpl.

Note: May break adding and deleting tasks.
Remove override of -[TaskBagImpl tasks] getter.

Returned tasks are no longer sorted before being returned,
but adding and removing tasks works again.
Load the task bag earlier in the app delegate.
Use KVO to get data in FilterViewController.
Merge branch 'feature/taskBagInterface' into feature/splitIpadView