Move `err` declaration to function signature.
Scrap unnecessary `RunnerPlugin` pattern for FileOutput (i.e. no more FileWriter) and
integrate batch support directly into the output plugin. First step toward an abstracted
batch output pattern that can also be used by other outputs.
Use []byte for the batch buffers instead of *[]byte.
Forgot to actually start the output. Added the waitgroup support for good measure.
Whoops, zero is still an integer...
Merge branch 'features/fileoutput-reboot' into features/whisper-output

Conflicts:
	pipeline/outputs.go
Documentation clean-ups for proper godoc formatting.
Switch to whisper-go fork, close cleanly on stop event.
Need to add to the ref count to ensure our pack doesn't get zeroed before we're done.
Merge branch 'features/fileoutput-reboot' into features/whisper-output
Merge pull request #39 from mozilla-services/features/fileoutput-reboot

Features/fileoutput reboot
Merge remote-tracking branch 'origin/dev' into features/whisper-output