Remove non-RPC SlaveWasPromoted and SlaveWasRestarted.
Fix issues with routing in VtGate tests

All queries were getting routed to shard 0
Create pid file if requested.
Merge branch 'pid'
VtGate test use get_keyrange_from_shard_name helper
Merge branch 'liguo'
queryservice: log tx pool offenders

When we return a tx pool full error, it's hard to tell who
caused them. We now perform a throttled logging of those culprits
which should help with troubleshooting.
queryservice: throttle tx_pool_full errors
pool: support for timeout and delete RoundRobin

We need timeout support for ResourcePool. This is a good time
to also delete the deprecated RoundRobin.
Support for UnsignedLong in GoRPC lib

Java BSON library does not support unsigned longs, but we use uint64 in
many places - keyspaceids, sequence id, etc. Currently uint64s are
decoded as signed longs. With this change we make 0x63 a
valid type and add support for encoding and decoding
UnsignedLong. Also, update references to Seq to use UnsignedLong instead
of long.
RowsAffected and InsertId are now decoded as UnsignedLongs

Just cast to signed long
KeyspaceId can be String or UnsignedLong

Currently KeyspaceId can only be a String. With this change, KeyspaceId
is made generic and added support for UnsignedLong.
Other changes:
Test to ensure queries are routed to the right tablet. Similar to
vtgatev2_test, all queries used to end up in the same shard, since we
were using String KeyspaceIds.
Make VtGateParams test helper its own thing
Add ExecuteKeyRanges to VtGate client
Add StreamExecuteKeyRanges to VtGate client
fix some typos
Validation checks in QueryBuilder

Remove all access modifiers in Query since only QueryBuilder can set these
Add validation checks in QueryBuilder while instantiating Query
Add tests for QueryBuilder
Rename stream to streaming
Add test code coverage plugin to GoRPC and vtgate-client
Add GoRPC lib and vtgate-client in top level project
Moving SlaveWasRestarted to rpc_server.go.

As it's not an actionnode any more.
Merge branch 'master' into replication