Add test for list_btables
Add test for show_schema
Estimate pairwise tests passing
trivial case of estimate columns test passing
Save/load models test now passes.
Added client unit tests, starting with save and load models, which now passes.
Cleanup temp test files that were created during tests (using a fixture).
Fix select order by direction
Fix sort by desc/asc issue; add error messages for functions when there are 0 models; add pretty-print for estimate columns.
Update analysis scripts to use BQL2 load models.
Update examples with new-formatted models files, and added backwards-compatible load models.
Add helper function to get all column names in order, and fix 'select *' behavior.