remove FilesetVersionInfo
add version info map to jobs
remove FilesetVersionInfo from graph traversal
fix Blitz to use new version info map

adds more Java version information
new patch version and schema
add upgrade scripts
correct destination patch level coming from 5.0

(thank you @sbesson)
Add imports check to travis build

This will compile a list of Python files in OmeroWeb and try to import
them to discover if any file has imports that do not work.

flake8 does not detect non-working imports.
Move import check after build step
Add pythonpath for django requirement
Merge branch 'develop' into travis-omeroweb-imports-check

Conflicts:
	components/tools/travis-build
Install pytest via pip for import check
rearrange 5.1 intra-patch upgrade scripts
python: Use os.path.isdir(p) rather than p.isdir()

The latter is broken with Python 2.7 on Windows.
OmeroPy: Document path.py changes
have extended metadata note new string map properties
add SQL for deleting map property entries
before deleting an entity, delete its map property entries
add note of which classes had subclasses with map properties
avoid object retrieval when there is no map property