poc.java now creates a 256x128 pixel image with unique pixel
values. however, it doesn't look that great!
On the plus side, ImageVerifier can now be used to check that an
image contains unique pixel values.
Unit test classes which help me check that
a) ... code works as expected
b) ... created images really do contain unque pixel values.
IDEA project file will help me work on this project from a different computer