State upgrade step: Add EnvUUID to charm docs.

Add an upgrade step to add the environment uuid to charm docs. Update
doc struct, call sites and tests respectively.
fixed conflicts
Merge branch 'master' of https://github.com/juju/juju into migrate-charms

Conflicts:
	upgrades/steps121_test.go
Merge branch 'master' of https://github.com/juju/juju into migrate-charms

Conflicts:
	state/upgrades.go
	state/upgrades_test.go
Merge branch 'master' of https://github.com/juju/juju into migrate-charms
move EnsureJujucSymlinks inside jujuc; move jujuc and debug inside context
Debug-log accepts names and/or tags for machines/units. Bug 1320543.
Fix data race

LP # 1386968 may be unrelated to a data race, but this needed to be fixed anyway.
update dependencies.tsv to use latest testing repo, fixing checkers.DeepEquals for Go 1.4
Merge branch 'master' of https://github.com/juju/juju into uniter-consolidate-context
Merge branch 'master' of https://github.com/juju/juju into migrate-charms
Merge branch 'master' of https://github.com/juju/juju into migrate-charms

Conflicts:
	state/upgrades.go
	upgrades/steps121.go
	upgrades/steps121_test.go
Merge pull request #1023 from fwereade/uniter-consolidate-context

move EnsureJujucSymlinks inside jujuc; move jujuc and debug inside context

Just code moves, should be trivial.
Merge pull request #982 from waigani/migrate-charms

State upgrade step: Add EnvUUID to charm docs.

Add an upgrade step to add the environment uuid to charm docs. Update doc struct, call sites and tests.
context: move test code around; uniter: action tests no longer use hook notifications, use results watcher instead
address possible race noted in review
Responding to review feedback.
Merge branch 'master' of https://github.com/juju/juju into 207-fix-data-race-lp-1386968

Conflicts:
	dependencies.tsv
Merge pull request #1031 from davecheney/207-fix-data-race-lp-1386968

Fix data race

LP # 1386968 may be unrelated to a data race, but this needed to be fixed anyway.

* updates `charm.v4` to pick up the api change to the `testing` sub package
* roll that change through the clients of `charm.v4/testing`
Add tests for --download and --filename.