SERVER-13681 Revert "SERVER-7378 Prevent WRITETODATAFILES and FlushViewOfFile from running at the same time"

This reverts commit 5352345eda2ffa24a72af1d5bbaccaa32bcb1006
SERVER-14623 fixed shell function ObjectId.fromDate for dates before 1978-07-04T21:24:15Z

ObjectId.fromDate is not correct for all dates

There is an under-run for dates less than 1978-07-04T21:24:15Z ('Math.pow(2,28) - 1' seconds)
Added extra test for upper date limit.

Closes #725

Signed-off-by: Benety Goh <benety@mongodb.com>
SERVER-9482 add flag to enable activation of FIPS mode (off by default)
SERVER-14633 rename prepareToYield() and recoverFromYield() to saveState() and restoreState()

Also renames PlanExecutor::getStages() to PlanExecutor::getRootStage()
SERVER-14616 replace BSONObj with ReplSetHeartbeatArgs in processHeartbeat
SERVER-14318 replace check() in replset_commands with ReplCoordinator::checkReplEnabledForCommand
SERVER-14673 eliminate unnecessary isShutDownOkay() method from ReplicationCoordinators
SERVER-14616 replace BSONObjBuilder with ReplSetHeartbeatResponse in processHeartbeat
SERVER-14616 add setters and toBSON to ReplSetHeartbeatArgs
SERVER-4217 updated detailed log format to include log severity and component name.

    Log severity is logged with a single capital letter.
        F - Severe
        E - Error
        W - Warning
        I - Info and Debug Level 0
        D - All debug levels > 0
    Component name is logged in upper-case padded with trailing spaces to fit within 8 characters.
Merge remote-tracking branch 'upstream/master'