FormatReader: clear the 'core' variable

Suggested by Curtis Rueden.
Zeiss CZI: tidy up metadata hashtable keys
Fix the Imaris metadata page
Make sure that SizeZ/SizeC/SizeT are set for single-file exports
Deltavision: make sure that the DetectorSettings.ID is set

See QA #4877.
Metamorph: look for the channel count in one more place

Reported by Stéphane Dallongeville.
Remove hard dependency on log4j from core Bio-Formats/SCIFIO
Remove loci.formats.utests.tiff.OMETiffWriterTest

All this test does is check for open file handles; we now have much more
comprehensive tests that cover the same thing (and without depending
upon log4j).
Remove commented-out log4j code from the ome-io component

These classes are beyond obsolete anyway, and will likely be removed in
the next major release.
missue #357 buffer overrun defensive coding
Merge pull request #362 from melissalinkert/tiff-overflow

Buffer overrun defensive coding
Update version numbers to 4.4.6
Merge pull request #365 from melissalinkert/4.4.6-version-number

Update version numbers to 4.4.6
Update version numbers to 4.4.7-{DEV,SNAPSHOT}
Merge pull request #366 from melissalinkert/4.4.7-dev-version-number

Update version numbers to 4.4.7-{DEV,SNAPSHOT}
SimplePCI: better calculation of Z/T dimensions
SimplePCI: do not populate more timestamps than planes
Merge pull request #363 from rleigh-dundee/lif-usercomment-dev44

Backport of PR #305 to 4.4
Merge pull request #367 from melissalinkert/cxd-dimensions

.cxd dimension detection fixes
ICS writer: fix support for writing RGB images

Reported by Harri Jäälinoja:

http://lists.openmicroscopy.org.uk/pipermail/ome-users/2013-February/003529.html