add numbers to keyFromKeyCode

[localpcguy]

Ran into an issue where I needed the numbers to in the keycode list as well (height/weight form).

Fixes #390

[ro0gr]

Adding a number key test-case seems good

[rwjblue]

Ya, definitely needs a test.

Also, would like @cibernox and @Turbo87 to double check.

[cibernox]

Looks good to me, it just needs tests.
Those keyCodes are for the number above the keyboard, do you know if the keycodes of the numpad keys are different? Just curiosity.

[localpcguy]

The keyCodes for number pad are the same. I'll get on the test(s)

[localpcguy]

Added tests for numbers. Let me know if there are any more concerns.

[localpcguy]

@cibernox I wanted to clarify re:keycodes between the top row and number pad:

The ASCII code (event.which) is the same between both, and that is what this codes uses as the keyCode. The event.code value IS different (at least on MacOS), showing Numpad1 vs. Digit1 for the 1 key for example. That won't affect this code as we are using the event.key value when this code references keyCode, not the event.code value. See http://keycode.info/ from @wesbos for a simple way to see key information.

[rwjblue]

Thank you!