build color_cmds, lut_funcs, and pixel_processor feedback in the splash
* app/Makefile.am: build color_cmds, lut_funcs, and pixel_processor * app/app_procs.c: feedback in the splash screen when loading parasites. * app/boundary.c: Optimized find_empty_segs. * app/brightness_contrast.[ch] * app/levels.[ch] * app/posterize.[ch]: moved pdb and lut calculation code. These files now contain only GUI functions. * app/channel.c: Optimized channel_bounds (fewer compares, better use of registers). Use color_region instead of channel_*_segment in channel_combine_rect. Optimized channel_combine_ellipse by skipping pixels inside of the ellipse. Use pixel_region_process_parallel in channel_combine_mask. Use a GimpLut in channel_invert, and channel_sharpen. * app/invert.c * app/equalize.c: moved the lut functions to lut_funcs.c * app/gimpdrawable.c, app/gimpdrawableP.h * app/gimpimage.c, app/gimpimageP.h: removed unused gimpmatrix variables/includes. * app/gimplut.[ch]: added new function gimp_lut_process_inline that operates on a single PixelRegion. * app/gimpparasite.[ch]: new functions to save/load parasiterc * app/parasitelist.[ch]: new functions to save/load ParasiteLists in/from files. * libgimp/parasite.[ch]: new functions to load/save parasites. * app/internal_procs.c: get some procs from new location in color_cmds.h. * app/pixel_region.[ch]: moved pixel_regions_process_parallel related functions to a new file. * app/color_cmds.[ch]: new files for PDB definitions/implementations of color correction functions. * app/lut_funcs.[ch]: new files to hold lut creation functions. * app/pixel_processor.[ch]: new files that contain the pixel_regions_process_parallel routines. Added some new capabilities that are currently unused.