May want to update docs.

[MonsterTKE]

I had to dig around in the .cpp file to figure out that a button is initialized via "Button button = Button(3, BUTTON_PULLDOWN)" rather than "Button button = Button(3, PULLDOWN)" as the documentation says.

I hate it when this happens, :( now I have to test every function in the library to make sure that it actually works as it should, due to not being able to trust the documentation.