vtgate v3: select plans
vtgate v3: more formal tests
vtgatev3: Gate* -> VTGate*
vtgate v3: wire plan building into vtgate
vtgate v3: add forgotten planner.go
parser: AND has higher precedence than OR
vtgate v3: add tests for or clauses
vtgate v3: make code reusable to prep for dmls
vtgate v3: update plans
vtgate v3: plans for delete
vtgate v3: drop keyspace_id col & add IsAutoInc.

We're going to see if keyspace_id column based sharding
can be deprecated in favor of an on-the-fly hash based
sharding which achieves the same thing.
Also, we should support auto-inc through lookup so we
can generate systemwide unique ids for our keys.
vtgate v3: insert planning skeleton
vtgate v3: insert plans
Merge branch 'master' into vtgate

Conflicts:
	go/cmd/vtgate/vtgate.go
vtgate v3: restructure schema data structures
Merge pull request #113 from youtube/vtgate

Vtgate