Adding custom keyboard foundation to allow you to build custom input keyboards for UITextFields and UITextViews. For example, if you want to show a number pad keyboard with a next button, use TKNumberInputWithNextKeyView.
Adding keyboard example to demo app.
Fix demo view controller.
Remove log statement in UIImage category.
Adjust the textField:shouldChangeCharactersInRange:replacementString: for number pads.
Adjust the textField:shouldChangeCharactersInRange:replacementString: for backspace key.
Avoid firing delete message when the text field is blank.