Reorganize extlinks and allow to pass SOURCE_USER for Github links

Reorganize extlinks to mirror organization of conf.py of ome-documentation.git
Fix Bio-Formats Jenkins job alias
merge dev_4_4 --exclude conflict needs-fixes broken: PR 312 (Return Bio-Formats version in bfCheckJavaPath())
merge dev_4_4 --exclude conflict needs-fixes broken: PR 313 (Sprint 4 bug fixes)
merge dev_4_4 --exclude conflict needs-fixes broken: PR 322 (Extlinks review)
merge dev_4_4 --exclude conflict needs-fixes broken

Repository: openmicroscopy/bioformats
Updating 03770c0..7c0e124
Merged PRs:
  # PR 312 sbesson 'Return Bio-Formats version in bfCheckJavaPath()'
  # PR 313 melissalinkert 'Sprint 4 bug fixes'
  # PR 322 sbesson 'Extlinks review'

Generated by OMERO-merge-4.4#106 (http://hudson.openmicroscopy.org.uk/job/OMERO-merge-4.4/106/)