Hotfix

• Fixed backwards compatibility for setuptools (see https://github.com/inmanta/inmanta/commit/654006181663db4ac40c8f82dea58b80bd4b588c)
• Added is_symmetric() and is_equal() functions for matrices that take into account small precision errors.
• In etcgraph.py, updated syntax to import ArpackNoConvergence from SciPy
• NOTE: cdd needs to be manually installed. Get it from https://github.com/daltonserey/cdd and in setup.py, change print "cdd setup finished..." to print("cdd setup finished...")