- The basic layer for Themes in place!

- currently only implemented for 3d window
- create as many themes you like, and name them
- default theme is not editable, and always will be defined at startup
  (initTheme)
- saves in .B.blend
- themes for spaces can become local too, so you can set individual
  3d windows at theme 'Maya' or so. (to be implemented)
- it uses alpha as well...!

API:
This doesnt use the old method with BFCOLORID blahblah. The API is copied
from OpenGL conventions (naming) as much as possible:

- void BIF_ThemeColor(ScrArea *sa, int colorid)
  sets a color... id's are in BIF_resources.h (TH_GRID, TH_WIRE, etc)

- void BIF_ThemeColorShade(ScrArea *sa, int colorid, int offset)
  sets a color with offset, no more weird COLORSHADE_LGREY stuff

- void BIF_GetThemeColor3fv(ScrArea *sa, int colorid, float *col)
  like opengl, this gives you in *col the three rgb values

- void BIF_GetThemeColor4ubv(ScrArea *sa, int colorid, char *col)
  or the one to get 4 bytes

ThemeColor calls for globals (UI etc) can also call NULL for *sa... this
is to be implemented still.

Next step: cleaning up interface.c for all weird colorcalls.

source/blender/src/language.c

@@ -31,6 +31,7 @@
 #include <string.h>
 #include <stdlib.h>
 
+#include "DNA_ListBase.h"
 #include "DNA_userdef_types.h"
 
 #include "BKE_global.h"		/* G */