Update the sandbox manager tools to use the new client library
Add loop detection to the message router

- work in progress, need to merge dev before completion
Merge branch 'dev' into issue_53

Conflicts:
	pipeline/router.go
Prevent infinite message looping from filter to filter
Remove the MGI
Remove unused struct
Incorporate review feedback

- Remove helper.Router() method
- Add InputRunner.Inject() method
- clean up logging
Merge pull request #108 from mozilla-services/issue_53

Issue 53
Merge branch 'dev' into features/dev-doc-update
Update docs to reflect removal of `PluginHelper.Router()` API.