Fix various writer bugs exposed by using 'changeOutputFile'
Exporter plugin: fix writing to multiple files

Fixes #10635.
ZeissZVIReader: ROI strings are UTF-16 little endian
ZeissZVIReader: Handle NULL labels

Also seek 4 bytes rather than 6 after the label, or else you end
up in missing the SourceTag and losing the correct position in the
stream.
Allow schema and schema page anchor to be defined for each property
Regenerate docs
Merge remote-tracking branch 'origin/dev_4_4' into anchors

Conflicts:
	components/autogen/src/doc/meta-summary.vm
	docs/sphinx/metadata-summary.txt
Fix many more broken anchors (especially in the ROI and SPW schemas)
Fix the annotation schemas
Fix anchors for reference attributes
Fix various LightSource anchors
Fix invalid link in the DICOM page
Hopefully the last of the anchor fixes
ZeissZVIReader: Handle presence of Layer names

The layer name is typically absent, but some layers have names.
Cope with non-null layer names.
Merge pull request #471 from rleigh-dundee/zvi-roi-missing

ZVI ROI fixes
Really fix the last annotation anchor
Zeiss CZI: parse Z positions from XML

See http://fiji.sc/bugzilla/show_bug.cgi?id=523
FormatWriter: close the output file before reinitializing
Merge pull request #473 from melissalinkert/anchors

More anchor fixes for metadata pages
Merge pull request #470 from melissalinkert/multi-file-export

Fix export of multiple files