add option to replace unknown pixels with notIndexed

[kilir]

Hi Ralf, I found the following modifications in gridify sometimes helpful when there are data sets with missing points (nan or discontinuous coordinates), setting those as nonIndexed phase. This may help in certain situations e.g. when using 'unitCell' in calcGrains isn't sufficient it also helps to works around the weird appearance when plotting grains calculated from gridified data which contains regions of no information (see example below).

% modified function gridify.m.zip

Cheers, Rüdiger

[bjoerneske]

in my files the non-indexed is phase 0, might be the case for others. Good idea to include the nan-pixels as not indexed.