Refactr peergrouper to export less API

Changes where made to make all of peergrouper changes external
but, after comments from @rogpeppe the changes have been
reworked to only export the necessary API from tests
and make a peergrouper_test packages only including the
part of the code that is indirectly using dummy provider
and therefore causing an import cycle when apiserver is
imported from state
Merge pull request #977 from voidspace/allocate-address-signature

Allocate address signature

AllocateAddress will be used by providers (the ones that support this functionality) to allocate a private address. Because of provider limitations we need to pass in the address to allocate, so the signature is changing appropriately.
Removed unnecesary commented code
Merge
Trivial implementation of ec2 AllocateAddress
Minor fixes
use errors annotate instead of fmt.Errorf
Revert "tools tarballs now live in a directory named after their stream"
fix dependencies.tsv
turns out that if you do this:
GOOS=windows godeps -t ./... > dependencies.tsv
that you get the right dependencies, since windows dependencies are a strict
superset of linux dependencies.  This may not always be true, but it is right
now, and that's good enough for me.
Merge pull request #980 from natefinch/fix_deps_again

fix dependencies.tsv

turns out that if you do this:
GOOS=windows godeps -t ./... > dependencies.tsv
that you get the right dependencies, since windows dependencies are a strict
superset of linux dependencies.  This may not always be true, but it is right
now, and that's good enough for me.
This fixes bug https://bugs.launchpad.net/juju-core/+bug/1384818

http://reviews.vapour.ws/r/277/
fix broken compile
Merge pull request #981 from natefinch/revert-968

Revert 968

This reverts PR #968, by request of QA (fixes bug https://bugs.launchpad.net/juju-core/+bug/1386766).  It is just a revert plus a tiny change to fix a test added after this change that became incompatible after the revert.
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.
fix conflicts
State, upgrade step: Add EnvUUID to Sequence doc IDs

Adds an upgrade step to add the EnvUUID to sequence doc IDs.
Update utils repo dependency.
Add HTTP request helpers to the API client.
Drop a superfluous error return.
Add some doc comments.
Fix up a few error messages.