all: merge dev.cc (929f3210) into master

This brings in cmd/dist written in Go, which is working on the primary builders.

If this breaks your build, you need to get Go 1.4 and put it in $HOME/go1.4
(or, if you want to use some other directory, set $GOROOT_BOOTSTRAP
to that directory).

To build Go 1.4 from source:

	git clone -b release-branch.go1.4 $GOROOT $HOME/go1.4
	cd $HOME/go1.4/src
	./make.bash

Or use a binary release: https://golang.org/dl/.

See https://golang.org/s/go15bootstrap for more information.

Change-Id: Ie4ae834c76ea35e39cc54e9878819a9e51b284d9