fixes for blender 2.93

[natejenkins]

Hey thanks for the plugin! Some very minor syntactical changes were needed for blender 2.93, but these occur in many places in the code. They are all of the form:

a = get_prop("coullet", "a",  0.80)

and they all need to be changed to:

a: get_prop("coullet", "a",  0.80)