V2.0.43

• Propagate timeout event correctly to db instances.
• Application Monitoring API (APM) implemented.
• NOT providing replSet name in MongoClient connection URI will force single server connection. Fixes issue where it was impossible to directly connect to a replicaset member server.
• Updated mongodb-core to 1.2.12.
• NODE-541 Initial Support "read committed" isolation level where "committed" means confimed by the voting majority of a replica set.
• GridStore doesn't share readPreference setting from connection string. (Issue #1295, https://github.com/zhangyaoxing)
• fixed forceServerObjectId calls (Issue #1292, https://github.com/d-mon-)
• Pass promise library through to DB function (Issue #1294, https://github.com/RovingCodeMonkey)