[CODE] Import paths are now relative instead of absolute in parsing/

[CODE] using SQLAlchemy for REST metadata retrieval
metadata retrieval is so much quicker now!

(see init/post-install-fixes.README for more details)

(could not access CTE methods such as .descendants(), etc.)

[FEATURE] Resources - Now the digest is computed for every added resource, and duplicates are not appended to nodes

[FEATURE] The 'extract_ngrams' method is now available from the queryset as well
[BUGFIX] The parsed resources are now marked as parsed in the database

Still needs to be fully tested.