Revert "Revert "Utilize __toString since that's kind of why that was implemented in the first place.""

This reverts commit 33cdcd63a7e7c1ab9780f12df2fdf4e9377b8969.

Conflicts:
	src/CentralDesktop/Graph/VertexSet.php
Revert "Revert "SplObjectStorage implemented getHash in PHP >= 5.4.0. Implement temporary backwards compatability to support control of object hashes so we can easily fetch vertices by data.""

This reverts commit 61248945594219da36747b8648fc99f65f0889c2.

Conflicts:
	src/CentralDesktop/Graph/Graph.php
	src/CentralDesktop/Graph/VertexSet.php
Fix bad revert