Added strings for tab labels.

Modified the hints to match the format of the actual information that will be contained in the date and time boxes
Changed the main activity.
Upped the sdk count
Removed the onclick handler set up in the xml in favour of setting it in the java code
Modified class to be a fragment (from being an activity ) so that it can be implemented as a tab.
Had to accomodate with change in methods to reflect a different life cycle.

Added the MainTabActivity as the parent activity which controls this Fragment
Added an updateMessage method to this service
Helper classes to examine Collections
The new Main Activity, this will be the main tab controller.

Coordinates communication between the child tabs
Callback to facilitate communication between tabs
This is the ORIGINAL main activity, refactored and renamed from being an activity to a fragment.