Prevent an NPE when referencing Image.AcquisitionDate

The acquisition date is now optional, and so may be null.  Without this
commit, bfconvert threw an NPE when the acquisition date was missing,
and the automated data tests logged a warning for each missing date.
Merge pull request #1260 from rleigh-dundee/cmake-cxx11-mac108

cmake: Only enable C++11 if enable_if is supported
Merge pull request #1254 from melissalinkert/rebased/develop/nd2-blocker

ND2: one more set of dimension parsing fixes (rebased onto develop)
Merge pull request #1255 from sbesson/deltavision_acquisitiondate

Fix ImageAcquisitionDate parsing for DeltavisionReader
merge develop -Dorg -Ssuccess-only: PR 1136 (Add initial support for reading BinaryOnly OME-TIFF datasets (rebased onto develop))
merge develop -Dorg -Ssuccess-only: PR 1154 (Leica: prevent exception when linking EmissionFilter)
merge develop -Dorg -Ssuccess-only: PR 1245 (Add reader for PicoQuant .bin files.)
merge develop -Dorg -Ssuccess-only: PR 1252 (Add Example code or writing Plate data to ome-tiff.)
merge develop -Dorg -Ssuccess-only: PR 1261 (jj2000: Fix compile on Java 8)
merge develop -Dorg -Ssuccess-only: PR 1264 (Prevent an NPE when referencing Image.AcquisitionDate)
merge develop -Dorg -Ssuccess-only

Repository: openmicroscopy/bioformats
Excluded PRs:
  # PR 1267 melissalinkert 'Volocity: flag most files as being pixels files' (status: failure)
  # PR 1249 PremyslFiala 'ND2 - Bug fixes' (user: PremyslFiala)
  # PR 1015 qidane 'Messy binary' (exclude comment)
  # PR 978 berl 'Add writing of .v3draw format for easy loading with Vaa3D.' (user: berl)
  # PR 857 melissalinkert 'Initial support for Zeiss .lms files' (label: exclude)
  # PR 858 melissalinkert 'Initial support for Veeco AFM data' (label: exclude)
  # PR 1054 qidane 'Additional annotation points throughout the model' (exclude comment)
  # PR 1268 carandraug 'multiple netpbm fixes' (user: carandraug)
  # PR 1265 qidane 'New units' (label: exclude breaking)
  # PR 1177 rleigh-dundee 'specification: Add metadata for HDF5 embedding' (exclude comment)
  # PR 816 melissalinkert 'Add support for multi-channel Volocity Clipping datasets' (label: exclude)
  # PR 1266 melissalinkert 'Analyze: set littleEndian flag correctly' (status: failure)
  # PR 1141 LeeKamentsky 'Reader for Amaris FlowSight .cif format' (label: exclude)
  # PR 1161 sommerc 'Initial CellH5 Reader class' (user: sommerc)
Updating 1d2c5f8..03d9c5c
Previously merged:
  # PR 1255 sbesson 'Fix ImageAcquisitionDate parsing for DeltavisionReader'
  # PR 1254 melissalinkert 'ND2: one more set of dimension parsing fixes (rebased onto develop)'
  # PR 1260 rleigh-dundee 'cmake: Only enable C++11 if enable_if is supported'

Merged PRs:
  # PR 1136 melissalinkert 'Add initial support for reading BinaryOnly OME-TIFF datasets (rebased onto develop)'
  # PR 1154 melissalinkert 'Leica: prevent exception when linking EmissionFilter'
  # PR 1245 imunro 'Add reader for PicoQuant .bin files.'
  # PR 1252 imunro 'Add Example code or writing Plate data to ome-tiff.'
  # PR 1261 rleigh-dundee 'jj2000: Fix compile on Java 8'
  # PR 1264 melissalinkert 'Prevent an NPE when referencing Image.AcquisitionDate'

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