Fix dot product symbol in docs.
Fix more dot product symbols.
Set value of PACKAGE_NEEDS_CYTHON to false
Merge pull request #18 from bernie-simon/bsimon-travis

Set value of PACKAGE_NEEDS_CYTHON to false
Merge pull request #15 from mdboom/fix-dot-product

Fix dot product symbol in docs.
Privatize some methods in the `Graph` class.