Python: add checkbox
Python: add checkbox

Due to Python immutability of parameters, the state of the checkbox must be enclosed by a list, e.g.:

checked = [True] # not checked = True
cvui.checkbox(..., checked)

Unfortunately developers must test the value using brackets later, e.g.

if checked[0] == True

It's the Python way, so let's roll with it. The original idea to use a list came from here: https://stackoverflow.com/a/3648488/29827

Dovyski/cvui,Dovyski/cvui,Dovyski/cvui