Implement images with transparent parts

[beuaaa]

SikuliX 1.1.4 introduces images with transparent parts (masked images).

Masking with SikuliX image search means, that the corresponding pixels in the image, that have a 0 in the mask pixel, will be ignored during search.

Here is a tutorial: 2014.readthedocs.io/en/latest/tutorials/masking/masking.html#tutorialmasking
It could be very usefull to implement this new feature in Lackey.