Fix command for retrieving filters.

Python raised this before:
> AttributeError: 'LightPathI' object has no attribute 'copyEmissionFilters'
Print Dichroic information.

Previously, the dichroic object was retrieved and ignored. ;)
Check if there was an actual Dichroic object returned.
Fix the dichroic type check.
Fix wrong indenting.
No fileAnnID in Metadata.py

BlitzGateway.loadOriginalMetadata always returns a None for
the first element of `om` for all data newly imported in OME5
since no extra file is created.
Merge pull request #2152 from joshmoore/rebased/dev_5_0/develop

Bug fix and improvement for the Metadata.py example. (rebased onto dev_5_0)