Description: takes one or two strips as input and inverts given frames 
Description: or make them bright white.

Author: Stefan Gartner 
Email: Stefan.Gartner@fhs-hagenberg.ac.at
Website: http://orpheus.fhs-hagenberg.ac.at/students/mtd/mtd97047/
License: BSD

if Alpha Flash is on, the frames either get fully transparent or 
replaced by frames from the second strip
if frames is is set to 2, frames 2,4,6,... are affected. 
if set to 3, frames 3,6,9,... and so on.