[bugfix] fix bug that returning from background
causes weird layout

- subclass UIViewController instead of UITableViewController
- stop edgesForExtendedLayout due to weird color. 
change frame.origin.y.
- change offset of tableivew
make scroll animation smooth
[bugfix] adjust size of tableview & position of
paybutton

- pay button was hidden behind tableview, so made
the tableview not fill the whole screen
- due to stop using UIRectEdgeNone, button now had
to be position lower
capitalize alert view title and use 'dismiss' for
cancel button title
use public key listed on https://webpay.jp/docs/payments_with_token
enable/disable scroll at WPYPaymentViewController
depending on keyboard is displayed or not
bump readme and podspec to 1.0.2