Remove PaymentViewControllerSubclass
Add launch images to support iphone6/6 plus and ipad
Add isiOS8 to WPYDeviceSettings
Use storyboard for WPYPaymentViewController

- create storyboard and delegate view creation
- change initializer interface to class method to
instantiate view controller from storyboard
Calculate position of explanation view instead of
hard coding constants
Calculate position of question mark button instead
of hard coding constants
Set tableview delegate and datasource in storyboard
Use storyboard for instantiating WPYCardFormCell
Create title label in WPYCardFormCell by code
WPYCardFormView adjustable to other screen sizes
Replace hard coded width with main screen bounds
in WPYExpiryField
Add 3x images for iphone6 plus
Adjust position of labels & button
Create brand logo views in WPYSupportedBrandsView

- Storyboard didn't work well with custom bundle
Adjust cvv label attribute to fit in Japanese

Security code label in Japanese will be 2 rows
Scroll tableview when name field is hidden by
keyboard suggestions.

On iphone4S, name field will be hidden by suggestion
shown on top of flick keyboard. This will not 
happen when QWERTY keyboard is used, but there was
no way to force the keyboard to be QWERTY.
Use new interface in ItemDetailViewController
Add launch images for 6/6 plus
Update xcode_sdk & scheme for travis
Uncheck Autocreate schemes