Added Entitlements and PNG files

Entitlements.plist
Resources/Default-568h@2x.png (compatibility with iPhone 5 screen size)
Improved AddTaskViewController

Added clear button in UITextField while in editing mode
Set alignment of UILabel to Center
Configured Info.plist

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
CRUD by Id instead of Description

CRUD operations on tasks are performed by Id instead of Description.
Merge pull request #6 from fabiogaragiola/master

CRUD by Id instead of Description and minor fixes.