Support for per-session randomized color schemes.  Mainly useful to allow each new session (from a particular profile) to have a different background color to make them easier to identify at a glance.  Randomization is specified in the color scheme as the maximum amount of difference in hue, saturation and value which a color is allowed to be randomly changed by.  No GUI controls for this yet.  Added a 'Black on Random Light' color scheme to make use of this facility out of the box.

svn path=/trunk/KDE/kdebase/apps/konsole/; revision=682403