Use latest Guava.
Some work on relations.

MapDB is really starting to suck, I think I'm going to rewrite the store
implementation in neo4j. Yaks, yaks, everywhere, and so many hairs to shave!
Some renamery and List -> Iterable.
No longer used.
Eliminate sig defs.

Sigs never define anything, they just use the defs defined in the real source
code.
Nixed some cruft.
Compile with some args.
Minor tweaks.
Rewrote MapDBStore in Scala; improved.
Make relations easily accessible from Def.
Stop insanity early, lest it wreak the havocs.
Avoid emitting relations to null type symbols.

Those resolve to the ROOT ref (which is perhaps wacky), and that then results
in bogosity.