Allow streams version to be parameterised so that it can be different for images and tools metadata
state: remove FromParams helper

`FromParams` forces `state` to depend on `apiserver/params` for its input parameters.

Ideally params should own these helpers, but that would require it to depend on state, which would currently cause an import loop.

Instead move the function to the calling packages temporarily.
Merge pull request #765 from davecheney/201-state-machine-remove-from-params

state: remove MachineJobFromParams helper

`MachineJobFromParams` forces `state` to depend on `apiserver/params` for its input parameters.

Ideally params should own these helpers, but that would require it to depend on state, which would currently cause an import loop.

Instead move the function to the calling packages temporarily.
Add subordinate boolean to the megawatcher for services and units.
added the environment uuid to the metric batch
uuid -> UUID
Merge pull request #768 from frankban/subordinate-info

Add subordinate boolean to the megawatcher for services and units.

This is required by the GUI machine view.
Add the API client side for backups.
Move backups into its own package.
Merge pull request #736 from ericsnowcurrently/backups-apiclient

Add the API client side for backups.

Note that backups has its own facade, so it isn't quite as simple as adding a new method on Client.
Tweak streams versions constants
Merge pull request #745 from wallyworld/tools-simplestreams-v2

Allow streams version to be parameterised so that it can be different for tools and images

This started out as a branch to use "v2" simplestreams metadata for tools to allow different metadata for 1.20 and newer vs 1.18 and older version of Juju. The fix is to change how simplestreams paths are resolved such that the streams version is now parameterised.

A different direction was decided on, but this change is still useful because it simplifies how Fetch() is invoked, provided a cleaner implementation of path resolution, and allows for easy changes of the streams versions in the future when needed. The changes are mechanical.
Merge pull request #769 from mattyw/add-env-to-metric

added the environment uuid to the metric batch

http://reviews.vapour.ws/r/36/
Factory methods using tags for user parameters.
Validate creator tags.
Updates to user tag.Name