Keypad
Initialize the Keypad.

begin()
Let the user define a keymap (assume the same row / column) count.

getKey()
Returns the keycode of the pressed key, or NO_KEY if no key is pressed.

getState()
Get the state of this keypad.

setHoldTime()
Set the hold time interval of this keypad.

addEventListener()
Add an event listener to this keypad.

makeKeymap()
Transforms the 2d key array into a key map that the library understands.