Add hook points to throttled logger to allow for other logging calls to be used.
Merge pull request #74 from plobsing/pluggable-throttled-logger

Add hook points to throttled logger to allow for other logging calls to be used.
rowcache: Improve plan for redundant LIMIT clauses.

Sometimes, people send PK queries, but still include a LIMIT 1 clause.
In such cases, we can treat such clauses as redundant and still benefit
from the rowcache.
planbuilder: couple more test cases & typo fix