deeper zoom levels

[darsor]

Use either arbitrary precision libraries or perturbation theory to allow deeper zoom levels.

The current limit is about 45 zooms, even with long doubles.

EDIT: I misunderstood the use of perturbation theory. It is effective at combating the slowdowns that come from using arbitrary precision libraries. It will still likely be slower than normal hardware floating point calculations.
Therefore, bignum libraries need to be implemented first.

[darsor]

resources:
http://mathr.co.uk/mandelbrot/perturbation.pdf
http://superfractalthing.co.nf/sft_maths.pdf