Use Homebrew Python rather than virtualenv

With recent changes brought to the main Homebrew repository, virtualenv Python
cannot be used by the Formula installer. To reduce maintenance burden, this
commit now installs Homebrew Python instead of a virtual environment. All
Python dependencies should be installed there during testing.
Fix scc installation
merge dev_4_4 -D org -I include -E exclude: PR 982 (Add support for Ice 3.5)
merge dev_4_4 -D org -I include -E exclude: PR 988 (webgallery prototype from github/will-moore/webgallery)
merge dev_4_4 -D org -I include -E exclude: PR 1126 (Fix long-missing DELETE EventLogs)
merge dev_4_4 -D org -I include -E exclude: PR 1176 (Import status tb dev 4 4)
merge dev_4_4 -D org -I include -E exclude: PR 1233 (OMERO.matlab: add object creation functions (see #10637))
merge dev_4_4 -D org -I include -E exclude: PR 1234 (Web image object id extension 11022)
merge dev_4_4 -D org -I include -E exclude: PR 1249 (Dataset creation 11048)
merge dev_4_4 -D org -I include -E exclude: PR 1261 (11074 export close (rebased onto dev_4_4))
merge dev_4_4 -D org -I include -E exclude: PR 1266 (Do not enter interactive mode if hql command output is piped (rebased onto dev_4_4))
merge dev_4_4 -D org -I include -E exclude: PR 1268 (Markup to sphinx)
merge dev_4_4 -D org -I include -E exclude: PR 1274 (Use Homebrew Python rather than virtualenv)
merge dev_4_4 -D org -I include -E exclude

Repository: openmicroscopy/openmicroscopy
Already up-to-date.
Merged PRs:
  # PR 982 rleigh-dundee 'Add support for Ice 3.5'
  # PR 988 will-moore 'webgallery prototype from github/will-moore/webgallery'
  # PR 1126 joshmoore 'Fix long-missing DELETE EventLogs'
  # PR 1176 jburel 'Import status tb dev 4 4'
  # PR 1233 sbesson 'OMERO.matlab: add object creation functions (see #10637)'
  # PR 1234 manics 'Web image object id extension 11022'
  # PR 1249 will-moore 'Dataset creation 11048'
  # PR 1261 joshmoore '11074 export close (rebased onto dev_4_4)'
  # PR 1266 sbesson 'Do not enter interactive mode if hql command output is piped (rebased onto dev_4_4)'
  # PR 1268 will-moore 'Markup to sphinx'
  # PR 1274 sbesson 'Use Homebrew Python rather than virtualenv'

Repository: openmicroscopy/bioformats
Already up-to-date.
Merged PRs:
  # PR 545 hflynn 'Adding OME 5 product menu'
  # PR 549 melissalinkert 'Zeiss LSM: use the longer display channel name'

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

Repository: openmicroscopy/ome-documentation
Already up-to-date.
Merged PRs:
  # PR 368 rleigh-dundee 'Cpp: Correct content and markup'
  # PR 384 sbesson 'Add menu for OME5 documentation sets (rebased onto dev_4_4)'
  # PR 388 hflynn 'Adding ome 5 to product menu (rebased onto dev_4_4)'
  # PR 390 mtbc 'Americanize spellings and fix typos'

Generated by OMERO-merge-stable#269 (http://hudson.openmicroscopy.org.uk/job/OMERO-merge-stable/269/)