Downloads preserves directories of original files
Merge remote-tracking branch 'origin/develop' into download_directory_structure

Conflicts:
	components/tools/OmeroWeb/omeroweb/webgateway/views.py
Merge remote-tracking branch 'origin/develop' into download_directory_structure
Use filesetPrefix to pick download directory structure
zip_archived_files() method within webgateway/views.py
Fix bug in download of 4.4 archived images
Moved zip_archived_files() into webgateway/util.py
Merge remote-tracking branch 'origin/develop' into download_directory_structure

Conflicts:
	components/tools/OmeroWeb/omeroweb/webgateway/views.py
DB 5.1__DEV11: unit support for PlaneInfo.exposureTime

This commit introduces the ome.model.unit.Time class
which contains a double value and a string unit for
representing time durations. The only location which
makes use of this is PlaneInfo.exposureTime. "ms" is
hard-coded until the xsd-fu unit support is in place.
Rename SQL files with new schema version
Add support for experimental properties markup in omero.properties
Do not blacklist individual properties
Removing print statements from webgateway/util.py
OMERO.editor deprecation: remove from the build system
Fix build target
Use DEVELOPMENT rather than EXPERIMENTAL to match OMERO.web properties
Display the Results tab for all images (including big images).
cpp_obj_reg.vm: fix whitespace
omero.properties: add DEV explanation
Use HTTP rather than HTTPS