Issue #464 Remove the core sandbox implementation (*nix pass)
Remove DecoderSet abstraction (and `DecoderSet()` method in the
PluginHelper interface) and replace it with Decoder and DecoderRunner
methods that will create and return a decoder or a runner by name.
MultiDecoder needs to support WantsDecoderRunnerShutdown for the
subdecoders.
Simplifies the code to always use the DecoderRunner channel for
decoding.
Dealing with unwrapped Decoders is tricky, so let's give a warning, and
let's not expose the Decoder method on PluginHelper.
Remove the core sandbox implementation (Windows pass)
Merge pull request #507 from crankycoder/features/fix-process-chain

Refactored ProcessInput and ProcessChain tests to fix cross-platform issues
Merge pull request #506 from mozilla-services/no-mo-decoderset

Remove DecoderSet abstraction (and `DecoderSet()` method in the
Revert borked change to AMQPInput that slipped through.
Merge branch 'dev' into issue_464

Conflicts:
	cmake/externals.cmake
	docs/source/installing.rst
Shut down some of the plugins that we started.
Merge branch 'dev' into stop-test-goroutines
Merge pull request #509 from mozilla-services/issue_464

Issue 464
Merge branch 'dev' into stop-test-goroutines
Issue #508 Refactor the sandbox code out of the pipeline package
Issue #508 Fix up the install for build without a sandbox
Issue #508 Add some require libs to the test plugins
git pull instead of fetch on external update
Merge pull request #511 from mozilla-services/stop-test-goroutines

Stop test goroutines
Issue #494 Allow sandbox access to the MsgBytes