replace relation icon pngs with svgs.
Merge pull request #111 from garyposter/rel_svg

Trivial change: replace pngs with svgs.  As a flyby, I also removed the old lbox cruft.

To qa, go to `http://localhost:8888/:flags:/relationCollections/` , add two services, relate them, and verify that you see the new green svg icon on the relation line.