Add constraint on unit fields

Since the two columns `${field}` and `${field}unit`
are assumed to go together, a constraint has been
added to prevent nulling just one. Hibernate will
throw an exception on **loading** a unit where
the "both null or not null" doesn't hold, so it's
certainly in our best interest to encode that in
the DB.
merge develop -Dnone -Ibreaking -Eexclude -Sno-error: PR 3216 (Misc DB fixes (5.1DEV__17))
merge develop -Dnone -Ibreaking -Eexclude -Sno-error

Repository: openmicroscopy/openmicroscopy
Excluded PRs:
  # PR 3263 joshmoore 'Units longnames' (user: joshmoore)
  # PR 3207 will-moore 'General pane web 2' (user: will-moore)
  # PR 2182 joshmoore 'Read only flag' (user: joshmoore)
  # PR 3181 joshmoore 'Update to Hibernate 3.6 (See trac2570)' (label: exclude)
  # PR 3228 mtbc 'fix #11779: graph operations use "compiler" rather than "rollback" strategy' (user: mtbc)
  # PR 3236 will-moore 'Fix 'Save to All' in Preview panel' (user: will-moore)
  # PR 3141 dpwrussell 'jstree upgrade (Functionality Review Only)' (status: failure)
  # PR 3249 manics 'Tables set all metadata 12606' (user: manics)
  # PR 2585 aleksandra-tarkowska 'making time_zone and first_day_of_week configurable' (exclude comment)
  # PR 3229 dominikl 'Use Units in ROI/MeasurementTool' (user: dominikl)
  # PR 3208 sbesson 'Update the OMERO install script to test Web login with CSRF (rebased onto develop)' (user: sbesson)
  # PR 3218 will-moore 'Units metadata panel' (user: will-moore)
  # PR 3000 jballanc 'Update artifacts for Lucene, Hibernate, and Spring' (user: jballanc)
  # PR 3262 sbesson 'Flake8 webadmin' (user: sbesson)
  # PR 3042 will-moore 'Download dataset project' (user: will-moore)
  # PR 3086 will-moore 'Create image by tiling 12459' (user: will-moore)
  # PR 3260 jburel 'mock object' (user: jburel)
  # PR 3264 jburel 'Support for collapsing unique light paths (rebased onto develop)' (user: jburel)
  # PR 3247 joshmoore 'C++ green 2' (user: joshmoore)
  # PR 3245 will-moore 'Get pixels size units' (user: will-moore)
  # PR 3265 joshmoore 'Read only inplace' (user: joshmoore)
  # PR 3254 snoopycrimecop 'Update develop submodules' (user: snoopycrimecop)
  # PR 3098 aleksandra-tarkowska 'Metadata reimport' (user: aleksandra-tarkowska)
  # PR 3221 dominikl 'Wrap description text to avoid horizontal scroll bar' (user: dominikl)
  # PR 3266 joshmoore 'More unit tests' (user: joshmoore)
  # PR 3156 aleksandra-tarkowska 'Templates cleanup' (user: aleksandra-tarkowska)
  # PR 2363 dominikl 'Java Gateway API' (label: exclude)
  # PR 3237 zeb 'Fix web attachment error msg develop' (user: zeb)
Already up-to-date.

Merged PRs:
  # PR 3216 joshmoore 'Misc DB fixes (5.1DEV__17)'

Repository: openmicroscopy/bioformats
Excluded PRs:
  # PR 1458 sbesson 'Fix Javadocs warnings' (user: sbesson)
  # PR 1476 sbesson 'Improve failure message and description of dist target' (user: sbesson)
  # PR 1443 joshmoore 'Genshi ZIP' (user: joshmoore)
  # PR 1472 rleigh-dundee 'cpp: compat: Add boolean type' (user: rleigh-dundee)
  # PR 857 melissalinkert 'Initial support for Zeiss .lms files' (user: melissalinkert)
  # PR 1177 rleigh-dundee 'specification: Add metadata for HDF5 embedding' (exclude comment)
  # PR 1407 melissalinkert 'TIFF: fix plane count calculation for pyramids with multiple planes' (user: melissalinkert)
  # PR 1381 melissalinkert 'Parse physical pixel sizes from CellSens .vsi datasets' (user: melissalinkert)
  # PR 1442 bramalingam 'Update roi handler' (user: bramalingam)
  # PR 1477 melissalinkert 'Flex: improved metadata handling' (user: melissalinkert)
  # PR 1474 sbesson 'Add bash script for updating copyright headers (rebased onto dev_5_0) (rebased onto develop)' (user: sbesson)
  # PR 1309 melissalinkert 'Allow tile-based access of large JPEG-2000 images' (exclude comment)
  # PR 1161 sommerc 'Initial CellH5 Reader class' (user: sommerc)
  # PR 1426 qidane 'Initial Rendering Definitions schema' (exclude comment)
  # PR 1461 csachs 'Changed ND2 metadata string handling to work properly with empty strings' (user: csachs)
  # PR 1473 rleigh-dundee 'C++: Minor documentation and whitespace fixes' (user: rleigh-dundee)
  # PR 858 melissalinkert 'Initial support for Veeco AFM data' (user: melissalinkert)
  # PR 1471 jburel 'mock object' (user: jburel)
  # PR 1015 qidane 'Messy binary' (exclude comment)
Updating c3521e7..a0565c9
Previously merged:
  # PR 1420 qidane 'Updating samples and adding units samples'
  # PR 1460 rleigh-dundee 'C++: Implement MetadataConverter'
  # PR 1465 melissalinkert 'NDPI: fix tile offset adjustment for files larger than 4GB'
  # PR 1457 melissalinkert 'IM3: fix memoization and whitespace'
  # PR 1468 rleigh-dundee 'C++: binary build and showinf fixes'
  # PR 1469 rleigh-dundee 'cpp: bioformats: Correct placement of warning pragmas in PixelProperties'
  # PR 1467 rleigh-dundee 'cmake: Replace FindXerces with FindXercesC'
  # PR 1459 jburel 'Fix writing of tiff description'
  # PR 1462 sbesson 'Add bash script for updating copyright headers'
  # PR 1463 sbesson 'Add script to bump version numbers'
  # PR 1365 ctrueden 'PrairieView 5.2 fixes and improvements'
  # PR 1437 stelfrich 'Changed handling of empty series names in ND2 files'
  # PR 1456 mtbc 'add note about using mvn eclipse:eclipse'
  # PR 1454 rleigh-dundee 'C++: Autoload schema catalogues and set up environment for tests'
  # PR 1366 ctrueden 'Miscellaneous cleanup'
  # PR 1452 joshmoore 'Use __import__ for generateDS to handle FS case issues'
  # PR 1448 melissalinkert 'Metamorph: allow both sanitized and unsanitized delimiters'
  # PR 1455 sbesson 'Remove source code hyperlinks from Java source files'
  # PR 1453 jburel 'Fix mock object to match changes from int to double for channel'

Repository: ome/scripts
Already up-to-date.

Repository: openmicroscopy/ome-documentation
Excluded PRs:
  # PR 1052 manics 'Add instructions for using Jekyll' (user: manics)
  # PR 1042 mtbc 'document graph traversal reimplementation for developers' (user: mtbc)
  # PR 1038 aleksandra-tarkowska 'updating web doc for embedding viewer' (user: aleksandra-tarkowska)
  # PR 1041 joshmoore 'Units documentation' (user: joshmoore)
Updating fb16f30..a3e7d3e
Previously merged:
  # PR 1044 hflynn 'Faq stuff'
  # PR 1047 manics 'Web iis docs'
  # PR 1049 snoopycrimecop 'Update auto-generated properties'
  # PR 1045 ximenesuk 'Explain default Python tests.'
  # PR 1046 hflynn 'Removing IDelete api link as service deleted'
  # PR 1048 snoopycrimecop 'Update auto-generated properties'

Generated by OME-5.1-breaking-push#225 (http://ci.openmicroscopy.org/job/OME-5.1-breaking-push/225/)