* Refactor sdb_foreach and related APIs
* Strengthen bounds check in sdb_dump_next()
* Switch to RzPVector
* Use length info in filter_noreturn()
* Fix cmp function
* Remove unused sdb_like() API
* Pass SdbKv to SdbForeachCallback
* Add sdbkv_dup_value() helper
The only place where this field was set to a non-zero value was the now
removed fb command, and it was never used for anything sensible. Thus it
is safe to remove.
