Remove all gratuitous `recover()` calls; resolves #323.
Remove unused imports and a little bit more of the panic detritus.
Remove `configPlugin` functions that don't really serve any purpose now that the
contained `defer` calls have been removed.
Merge branch 'dev' into features/no-recover

Conflicts:
	pipeline/pipeline_runner.go
Merge pull request #369 from mozilla-services/features/no-recover

Remove all gratuitous `recover()` calls; resolves #323.