Initial implementation of JSLint gulp plugin

In keeping with [single responsibility principle](http://en.wikipedia.org/wiki/Single_responsibility_principle) it has two responsibilities:

1. Pipes all the specified streams together, i.e. `streamsAsTask(s1, s2, ..., sN)` will do `s1.pipe(s2); s2.pipe(s3); ...; sN-1.pipe(sN);`
2. Returns a function that can be used as an [orchestrator](https://github.com/orchestrator/orchestrator) task (gulp is really just a subclass of orchestrator); if any stream fails with `error` event, this will be forwarded to orchestrator as a task failure