Set to-do item object of AddToDoItemVC to null

- This is needed when we want to add a new to-do item to list
Changed camera icon and reminderVC transition

- The ReminderVC will now transition like a calendar flap
Fixed the iCloud entitlements
Added ability to drag cells up and down table

-To-do items can be re-arranged by dragging and dropping the
appropriate cell(s) in the table
- Also made some bug fixes
Merge pull request #14 from akshay23/akshay/feature

Added ability to drag and drop cells in order to re-arrange items