Statistical image check for heuristic image drop
Empty image drop based on histogram statistic.

Pixel intensities mean and stddev are estimated for
filtered image. Possibly empty images are dropped
based on these and THRESHOLD values.
Merge pull request #20 from evmarkov/heuristic

Heuristic
Projects cleanup

Most of old projects have been removed. "test04"
is renamed to "test_app"
Merge pull request #21 from evmarkov/master

Projects cleanup
improvements for tools
add missing image