Fixed visualization by choosing the color appropriate to the detection
score.
Previously the example showed all detections with the same color
disregarding the confidence. This led to the impression that the object
detection did not work at all because there are many detections with low
confidences.

PR to master was
https://github.com/Itseez/opencv/pull/320

Introduced new Java API
void org.opencv.core.Core.setErrorVerbosity(boolean verbose)
used to suppress output to stderr from OpenCV's asserts

Common part of all source files is extracted to special header

- add syntetic images generation function to ts
- use generated syntetic images