Revision history:
 1.2.1  - Bugfixes for shaped mazes on offset layers.  This was a very strange 
          fix...  x offset and y offset apparently have different solutions.
          (get_row now has +xoff, while get_col has no +yoff.  Explain that!)
        - Bugfix for non-interactive.  Corrected the nparams check, corrected 
          the order of the parameters.  The status return codes mean very little
          right now, that run() function should be re-done in the future.
 1.2.0  - Made mask_maze actually work, by getting rows and columns at a time 
          instead of tiles.
        - Rewrote http://www.poboxes.com/kevint/gimp/maze-help.html with a 
          man page type organization and a gimp.org-like style-sheet.
 1.1.90 - Split up the code into a few more different files.
        - Added Prim's Algorithm in normal and tileable modes.
        - Added algorithm choice to the PDB parameters.
          ^^ Note this changed the PDB interface. ^^

        - Added mask_maze, which allows mazes to be drawn in irregular selections.
 1.0.0  - Calling it version 1.
        - Further tweaked maze_help, hopefully it doesn't still crash.
 0.6.2  - drawbox rewritten with memcpy and a row buffer.  By the way, Maze is now
          faster than Checkerboard.
        - Added Help button using extension_web_browser.
        - Added DIVBOX_LOOKS_LIKE_SPINBUTTON flag.  Doesn't look too hot, set to
          FALSE by default.
 0.6.1  - Made use-time-for-random-seed a toggle button that remembers
          its state, and moved seed to the second notebook page.
 0.6.0  - Width and height are now seperate options.  
          ^^ Note this changed the PDB interface. ^^
        
        - Added interface for selecting sizes by "divisions".
        - Added "Time" button for random seed.
        - Turned out that GParam shouldn't have been "fixed".
 0.5.0  - Added the long-awaited "tileable" option.
           Required a change to PDB parameters.
        - fixed some stuff with GParam values in run();
 0.4.2  - Applied Adrian Likins' patch to fix non-interactive stuff.
        - -ansi and -pedantic-errors clean.  Woo-hoo?
 0.4.1  - get_colors() now works properly for grayscale images.
          I'd still like it to do indexed too, but I don't know
          if that's worth breaking a sweat over.
        - We're -Wall clean now.  Woohoo!
 0.4.0  - Code for the painting of the maze has been almost completely rebuilt.
            Hopefully it's a more sane and speedier approach.
            Utilizes a new function, drawbox, which colors a solid rectangle.
            (Good excercise, in any case.)
        - Order of paramaters changed, defaults are used if not given.
        - Discovery made that that was an utterly useless thing to do.
 0.3.0  - Maze is centered with dead space around outside
        - Width slider works...  And does stuff!  
        - Allows partial mazes to be generated with "broken" multiple
             and offset values.
 0.1.99 - Has dialog box with seed, multiple, and offset.
 0.1.0  - First release.  It works!  :)