Introduce global{Orientation, Reverse}.
Modify graph creators to load edges properly.

Undirected graphs (pseudographs or weighted pseudographs) load edges
only once since JGraphT is smart enough to know that they are
bidirectional.

In directed and reversed graphs (directed pseudographs or directed
weighted pseudographs) it is now possible to specify individual edge
orientations (directed, reversed or undirected).

It remains to finish writing all the tests to make sure this works as
expected. Once that is finished, #27 will be done.
These should have been public.
Write remaining tests
Fix formatting and suppress unnecessary warning
Remove unnecessary imports
Merge pull request #48 from agouge/fix/#27

Enable graph creators to assign individual edge orientations