Fixed issue #2176: Color config for "View Patch" Window & TortoiseGitUDiff

Based on TortoiseSVN rev. 25977.

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Sync with TortoiseSVN

Signed-off-by: Sven Strickroth <email@cs-ware.de>