Reduced memory footprint for RBF transform when handling huge sets of coordinates
Allow passing default value for unmappable pixels.  This allows the background to be black for images and maxval for zbuffers.
Tests that run on 4080x4080 TEM images to ensure scalability.
Use the correct max value for distance buffer
Fixed issue with RBF weight calculation that was incorrect with last checkin for chunking the calculation across many iterations
Merge branch 'Assemble'