Extended export commands to support exporting from trees with mixed feature types
Merge branch 'volaya/output_improv'
Fixed issue with featuretypes not being written to object database

Minor change to WalkGraphOp class. Now an ObjectDatabase is injected instead of a GeoGIT object
Merge pull request #301 from volaya/feature_type_odb

Tested using the steps in #268.  This seems to fix that issue as well.  Also tested by deleting the index before performing the walk-graph operation.

fixes #268