Accessor and mutator changes

-Added a way to track multiple targets in one point cloud trough
mult_tracker class
-Changed accessors and mutators in detection_module to be more in line
with the rest of the project
-Added regionWidth() and regionHeight() to return width and height of
the detection region
-Removed unnecessary parts from disparity calculation and reprojection
equations, because m_calib_Q.at<double>(0,0) and
m_calib_Q.at<double>(1,1) is actually always 1 by definition
-Fixed draw_mask
-Added HsvToRgb to be able to generate colors for multiple targets more
easily
-Added another overload to output module, so its possible to output 4
data structures in one file