Better error messages at TaskManager startup and registration
Fix race at TaskManager registration during startup
Fix serializability for SlotSharingGroup
Adjust tests to new JobGraphModel
Add co-location-constraints as a special case of slot-shared scheduling
Fix bug in topological sort
Port streaming package to new JobGraph API and adjust all runtime-level tests
Improved distribution of IDs. Previous implementation lost bits due to double-to-long multiplication and rounding.
Fix failure exception message report back to client
Make Co-Location constraints resilient aginst out of order scheduling and depply integrate them with slot sharing
Fix miscellaneous checkstyle errors/warnings