Fixed Bug in the the colour dialog usage.  Now on "cancel" press the colours are maintained and no longer turned to black.
Fixed Bug in the the colour dialog usage.  Now on "cancel" press the
colours are maintained and no longer turned to black.

Rewrote the code for "calculate" to use the concept of supercells.
Coupled this with changes to the settings GUI to allow supercells to be
shown

JohnKendrick/PDielec