- added shadow mask type option to choose between "Screen" and "Source"
tile mode ("Screen" is the default as before)
- added bloom type option to choose between "Addition" and "Darken"
blend mode ("Addition" is the default as before)
- the alpha channel of a shadow mask is now filled with the background
color of the screen by the amount of the inverted alpha value
- added monochrome-matrix.png which can be used in combination with
"Source" tile mode and "Darken" blend mode to simulate a STN LCD, for
example