Elmclient

Added RM-only create_folder, replaced load_folders with find_folder, also an example to use/test the create_folder functionality
Added RM-only changeset create/delivery, with an example

Extended the DN type system to retrieve link types; these are now included in the oslcquery --typesystemreport
Fixed issues in reqif_io: selecting a config didn't work, and there was a typo for QUERY_PASSWORD
Added example db_simple_modifylink.py - this adds/removes a DN link between core artifacts; this is what required extending the typesystem to retrieve linktypes, so the link type to be created could be found by name

Added examples/dn_simple_deleteartifact.py

-n null checking wasn't detecting empty link columns/-v notnull checking wasn't detecting non-empty columns

Ran tests against 7.0.2SR1 only