TIFF writer: store 16-bit lookup tables
ImageConverter: ensure that 16-bit lookup tables are preserved
Fix lookup table reading for OME-TIFF files

Without this change, only the first lookup table was returned regardless
of how openBytes was called.
ImageJ exporter: fix lookup table population for 16-bit data

Fixes ticket #11658.
merge develop -D org -I include -E exclude: PR 528 (Tile performance improvements for VMS and NDPI)
merge develop -D org -I include -E exclude: PR 796 (Zip: improve reader and handle performance)
merge develop -D org -I include -E exclude: PR 804 (Leica LIF: 'C' goes before other dimensions if SizeC and SizeT > 1)
merge develop -D org -I include -E exclude: PR 807 (CellWorx: ignore thumbnails and missing channel names (rebased onto develop))
merge develop -D org -I include -E exclude: PR 809 (Tidying ITK user doc page)
merge develop -D org -I include -E exclude: PR 810 (Preserve lookup tables when exporting from ImageJ)