Merge remote-tracking branch 'aosp/upstream' into master

056963fe Merge pull request #113 from colincross/parallel
fcaf58b5 Merge pull request #114 from colincross/gofmt
5b0231b0 Enforce gofmt in travis
c93490c6 Parallelize cloneModules
a028bf49 Fix gofmt
49c279ab Parallelize BottomUpMutators
f8b5042c Implement EarlyMutators with BottomUpMutators
93c4cf68 Revert "Add dependency visiting methods to BottomUpMutatorContext"

Change-Id: I7c6f31e6f9366e26d355024f7518bf81fc64e82d