-coloring algorithms

 -saving/loading

 -accepting them in infix notation

  -http://www.maths.abdn.ac.uk/~igc/tch/mx4002/notes/node72.html has an
  algorithm for converting infix to postfix.

-when loading new palette, if coloring algo uses PALETTE_COUNT, and new
 palette has different count to last, automatically recalculate image

-use long double when double's precision runs out (~30% slower)

 -probably by templatizing all the calculation functions

-optionally store iter/re/im for each calculated pixel, so you can tweak
 coloring without recalculating image (needs 12 bytes per pixel -> lots
 of memory needed for large AA values)

POSSIBLY IN THE FUTURE:

-Distributed rendering

 -Multiple threads

 -Multiple machines
