Color change functionality in "STEP2"

[DariuszWilczewski]

Suggested improvements to color handling in "STEP2" (based on V.097/0.98)

1. CTRL+R sets random colors –OK, but I could also use a keyboard shortcut to set a solid color, instead of clicking “View → Point Cloud → Color →”.
2. The random color option very often picks very similar colors for neighboring segments, like blue and dark blue, green-khaki, yellow-light orange a
   Usualy I must press ctlr+R few times to get contrast colors, but I usually use this in “Manual Pose Loop Closure”, when I want to compare adjacent scans, so 3...
   3 .During “Manual Pose Loop Closure”, the “Render source as red, target as blue” checkbox should work immediately when selecting source and target segments, so if I close this window, I am back to solid state color of whole scan. Now it doesn’t work until I launch “Manipulate active edge” mode. every time, I pick new edge, I must ctrl+R to see if they are OK, few times cause I pick diferent segments before creating edge, at the end I pick solid color again, and proceed to next posible edge...
   3b. The source should be blue (or possibly green), and red should indicate the part of the scan that will change. In standard engineering conventions, red usually means designed/new/changing/moving. Here we move the blue part of scan, awkward a bit.

[yuckinus]

Good points. Will take care of it as soon as I get the chance if nobody else will do it in the meantime