Add page documenting how to use xsd-fu

Largely copied from http://trac.openmicroscopy.org.uk/ome/wiki/XsdFu

Fixes #2228.
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 556 (Add ``mkfake`` tool)
merge develop -D org -I include -E exclude: PR 589 (Zeiss LSM: use the longer display channel name)
merge develop -D org -I include -E exclude: PR 596 (Minor defensive programming changes for TIFF-based formats)
merge develop -D org -I include -E exclude: PR 597 (Update OME-XML population to match 2013-06 changes)
merge develop -D org -I include -E exclude: PR 598 (Add page documenting how to use xsd-fu)