WIP: webapp/src/logo/depviz: Update the depviz logo

[wking]

Linking to the new SVG (in its outside-the-webapp location).

Also update the filenames from #72 to drop a redundant -logo.

[wking]

Hmm, we probably need one of the more compact ideas from #14 as well. The version which landed via #72 is too crunched in the header bar:

And once we get a suitable tiny logo in there, I'll need to adjust the offsets as well so the jump field can take advantage of the extra space.

[jbenet]

the headerbar needs to change significantly. the whole site look is temporary-- it is not really usable atm.