nice things coming in Go 1.7: toolchain improvements

[Michael Hudson-Doyle]

Hi all,

I know we're all heads down for release, but I thought I'd report
something interesting: the go linker in go tip / 1.7-to-be is so much
faster than the one in 1.6 that it nearly halves the time to run "go
test github.com/juju/juju/...", taking the wall clock time on this EC2
instance I had set up from "28m1.069s" to "15m19.542s"! So that's
something to look forward to :-)

(Actually go tip chokes on the juju tests currently, I wound back a
few days to make these numbers -- upstream bug report being written
now)

Cheers,
mwh