2001-10-30  Simon Budig   <simon@gimp.org>

        * app/pdb/tools_cmds.c
        * app/tools/gimperasertool.c
        * app/tools/gimperasertool.h
        * tools/pdbgen/pdb/tools.pdb

        Added a "color erase" feature to the eraser. This is ported from
        the colortoalpha plugin and is utterly cool.

        The "Color Erase" Option should be disabled when the drawable
        has no alpha channel, however, I have no idea how to do this.