add reader for Umbel and the Umbel/DBPedia linkage
Merge branch 'version5.3' into umbel

Conflicts:
	data/Makefile
bring Umbel reading up to date
fix awful Makefile bugs in handling Open Mind data
Unbreak the tests that are still possible on Python 2

Most of the tests will now pass in Python 2. The excluded tests are:

- Tests for the readers -- the tester uses Python 3-specific code, and
  this makes sense because the readers should never be run under Python
  2 anyway
- Doctests, because Python 2 string literals look different
make a .csv file of the non-ShareAlike edges only
keep more assoc-space axes at intermediate steps
fix some paths in the Makefile
restore "flat_msgpack" to "flat_json" in the Makefile
update tests for 5.3 URLs
WIP: a smarter interface between the API and AssocSpace
add assoc_query.py
fix and test the AssocSpaceWrapper
Merge branch 'assoc_wrapper' of github.com:commonsense/conceptnet5 into assoc_wrapper

Conflicts:
	conceptnet5/api.py
	conceptnet5/assoc_query.py