additional performance tweaks

- removed all transparent images and replaced them with argb colors
instead
- added new groupbox to support transparency on windows xp (hopefully)
- label backgrounds now match their parents background color
minor cleanup and perf. changes

- updated theme colors to be more consistent
- added custom panel to apply the same tweaks for double buffering and
transparency as groupboxes
- fixed the naming of tab controls
- updated the themes to support alpha colors
- general cleanup
fix for input

fixes an issue where the new tab control handles all keyboard input
(whether it handled it or not). this fixes the reported problem where
some text controls couldn't have their data changed (population, embark
size, etc.)
Merge remote-tracking branch 'splinterz/master'

* splinterz/master:
  fix for input
  minor cleanup and perf. changes
  additional performance tweaks

Conflicts:
	Masterwork Dwarf Fortress.exe