* app/*.[ch]: Actually use the enum types GimpImageType,
GimpImageBaseType, LayerModeEffects, PaintApplicationMode,
BrushApplicationMode, GimpFillType and ConvertPaletteType, instead
of just int or gint. Hopefully I catched most of the places
where these should be used.
Add an enum ConvolutionType, suffix the too general constants
NORMAL, ABSOLUTE and NEGATIVE with _CONVOL. Use NORMAL_MODE
instead of NORMAL in some places (this was what was intended). Fix
some minor gccisms.
* app/apptypes.h: New file. This file contains the above
enumeration types, and some opaque struct typedefs. It was
necessary to collect these in one header that doesn't include
other headers, because when we started using the above mentioned
types in the headers, all hell broke loose because of the
spaghetti-like cross-inclusion mess between headers.
(An example: Header A includes header B, which includes header C
which includes A. B uses a type defined in A. This is not defined,
because A hasn't defined it yet at the point where it includes B,
and A included from B of course is skipped as we already are
reading A.)
Tor Lillqvist