* Removed unused parameters
* Fixed several cost calculation errors in ror_intersect_add
* Better code structure for ror_intersect_add and get_best_ror_intersect
* Fixed a problem with wrong query results for partially covering keys in ROR-index_merge
* ROR-intersection retrieval plan choice algorithm now uses less disk IO
- and properly processes clustered PK range scans
* Fixed several minor range optimizer problems
* Added more comments
* Code cleanup