Vastly simplify how we determine what version it is.
We only support git, nothing else is needed/wanted because of upkeep
headaches.
tags are now verified with exact-match, NULL otherwise.
branches are now populated with the symbolic-ref, NULL otherwise.
Fix modification detection.
Vastly simplify how we use version data.
Fix autorevision.cache file to not be deleted on make clean (before, it would be
deleted if you were using a tarball and did make clean)
No build modification changes are nessesary, it is backwards compatiable to
what we had before. (As long as you use git or use the tarball)
closes ticket:4136
vexed
dak180
cybersphinx
Cyp