Improve display in iOS 6 and add “CompletedAway” state for actions

Main.storyboard
- Introduce constraints to improve layout in iOS6
- buttons are now “Custom” rather than “System” which means in iOS6 the background colouring is not obscured by the rendering of a button with a rounded corner rectangular table
- “Away” button added to ActionView

PPRScheduleTableViewController
- add support for CompletedAway action state and “Away” button
- rendering of cells adjusted to work in iOS6 to give correct colour representing state

Added PPRStatusShowViewController
- supports the StatusBarButtonItem on views in a similar fashion to PPRStatusShowingTableViewController

PPRAppDelegate
- support “CompletedAway” state
Merge pull request #27 from davidbernard/iphone_3_layout

Improve display in iOS 6 and add “CompletedAway” state for actions