[krbdev.mit.edu #7002] verto sshould have a pointer to upstream sources and be in NOTICE

[Sam Hartman via RT]

As best I can tell, none of README, NOTICE or the like actually have a
pointer to the verto sources.
I think that

1) There should be a README in src/util/verto pointing to the upstream
I pprefer this to including the information in the top level README but either would be fine.


2) NOTICE should be updated to include the verto copyright and license