Toggle Mode for buttons

[georgkrause]

Some midi controllers send a on message on pressing a button and a off message on releasing the button. sending this signal to any button of luppp actives this button when i press it but deactivates it when i release it. So i want luppp to handle a toggle mode. i want to set the toggle for the button in the .ctrl-file. when its on, i want that luppp ignores the off message and toggles the button on every on message (turning off if its on, turning on if its off)