Add Cube detector, Cube tracker

[Preclaa]

Add two new modules - cube_detector and cube_tracker. Cube detector detects colored cubes in image from Kinect. Cube tracker periodically calls detector and stores positions of detected cubes. New Object Type was added (CubeTracker) that can return Pose of nearest/farthest cube from given point.

Detector runs on port 5020, Tracker on port 5021. OT is integrated in fit_demo.

[ZdenekM]

@Preclaa Also, before merging this, please squash your commits into one. Thanks!