Segment names are once again strings instead of symbols. All tests passing.
Fixed some bugs related to getting the data in a segment that doesn't start at zero
Fix the revision number on default (implied) nodes
Make default revision numbers more efficient
Fixed the delete-node code, which never actually worked
Changed cross-references: if there's a cross-reference anywhere within a node, it'll show up. Likewise revision - take the highest revision number from the entire node, not just the actual address.