SERVER-14788 Wire initial configuration loading into startReplication.

via Andy Schwerin.
SERVER-7285 Add mongod.service file for Linux

Add a systemd .service file. This is used in place of System V init scripts on most current Linux distributions.

Closes #740

Signed-off-by: Benety Goh <benety@mongodb.com>
SERVER-14857 prevent stepdown.js from failing when grabbing the wrong master during shutdown
SERVER-14497 UpdateStage
Merge remote-tracking branch 'upstream/master'