-----------------------
* Cleaned out tests: removing ZTC cruft, turning them into proper unit tests
and removing tests that tested other non-index components.
[mj]
* Fixed level handling for queries where a (path, level) tuple is passed in
instead of using the general level parameter.
[mj]
* Refactored and documented the index codebase. Several bugs were discovered
and solved in the process. Missing functionality was also added, all search
options should now work across all scenarios.
[mj]