Rename relation to predicate.
Interface maintenance on segment and chunk.
Fix operator precedence issue.
Make template-heavy Boost Spirit happy.
Add names for ID space boundaries.
Fix linker error with static member.
Support bitstream-based event extraction.
Consolidate segment extraction interface.

I'm not really happy with the internal complexity of the reader, but it works
for now. In the future, we should figure out a better way to navigate through
the chunks of a segment, ideally seperating the iteration into an orthogonal
concern.
Fix issue with ambiguous befriending.
More work on the query processor.
Add feature to save cmd line history to file.