[ ] Add options for storing as 3d features with Z, ZM
[ ] Add rendering options to processing - maybe as second processing algorithm
[ ] Add support for adding layer properties to processing generated layers in the same way as the dialog (note that properly this needs getting the source layer name where defined)
[ ] Duplicate point value - should not recalculate for every incremental change of value in dialog.
[ ] Enum parameters currently passed as integers. Would be much better for the future if passed as string codes such as 'quantile','fixed', etc