! Undefined errors
- Windowbg/2 now different on admin side;
-- Windowbg uses all rounded
-- Windowbg2 has no round corners for top-left/right
! Removed some alternates.
Note: Due to IE8/9 compatibility Curve2 has no zebra strips,
for front-end alternate codes still exist but windowbg/2 shares
same bg-color. Code still exist for theme makers, who wants to support
old browsers does not support CSS3 properly. Which is a shame to me to
see still supporting crap browsers...

Signed-off-by: Antes <antes@simplemachines.org>