* Add command line options for a)loading up a gk2 file, b) specifying one
  of width/height (maintain aspect ratio).

* Add command line option to output direct to file, when loading gk2 file,
  and without the gui appearing, ie batch mode.

* Make .gk2 files human readable instead of binary. (what put me off was
  difficulty of displaying long doubles with printf I think?)

* Allow user to save colour palettes.

* When re-positioning the image, shift areas of the image which will still be
  visible, rather than recalculating them...

* Remove use of combo boxes for editing drawing method formula.  I am not
  familier enough with postfix or Reverse Polish notation to be able to
  use it well.  So until I've got a postfix to infix converter running
  it's combo boxes all the way.
 
* * * * * * Lots of tidying * * * * *

* Cropping

* Multiple threads for rendering. Should allow a pretty linear increase
  in speed on SMP machines. (from gfract's TODO)

* Periodicity checking.

* Investigate how to get rid of the clobber-warnings in my_png.c. Just
  adding volatile didn't work. (from gfract's TODO)