Bug: When switching to Julia, set re/im start/end to default
Bug: above 65535 iterations, some points in the Mandelbrot set are not black
Exploit symmetry:
    if perturbation != 0 no symmetry
    else if mandel then symmetry with x axis
    else if julia then rotation symmetry with (0,0)
Problem with Expose und XtPopdown
File dialogbox
Pulldown menu
Resources
Batch mode (different start code)
Correct resize and scrollbars
modularize GUI
Preview with coarse grid:
  introduce a stepWidth field in SharedInfo
Tree of images stored in a file:
  introduce a filename filed and a flag in SharedInfo
Store image in compressed format (zlib), else they are too big and the
tree becomes senseless.
Panning
Integrate with other fractal generators which have more or unique features
Use autoconf

