Merge branch 'master' into development

* master:
  Merge Development (#57)
  Revert "do not lock while writing to a socket (#52)"
  do not lock while writing to a socket (#52)
  Merge Development (#48)
  Merge development (#39)

# Conflicts:
#	.travis.yml
#	cluster_test.go
#	harness/daemons/.env
#	harness/mongojs/init.js
#	session.go
#	session_internal_test.go
#	session_test.go