CRUD by Id instead of Description and minor fixes.

- CRUD operations on tasks are now performed by Id instead of Description
- Added Entitlements and PNG files
- Added clear button in UITextField while in editing mode
- Set alignment of UILabel to Center
- Disabled landscape orientation (GUI is messed up)
- Added bundle display name (Tasky)
- Added minimum OS version (7.0)
- Set default text when saving a task if no description is provided