Fixing issue where plugin was still writing to stream when closed off

[jjgonecrypto]

This is incomplete (missing the options.banner prepend, and broken tests) but I did find the culprit of #350.

Basically, instead of using the bundle callback, we need to pipe instead (see here), as the latter ensures that the entire pipeline is complete before piping. In this case - that all the files in the pipeline have completed. (You can see factor-bundle here is adding the files to the browserify pipeline).

That said, I'm not using the grunt writer - I'm not that familiar with grunt - is that a concern?

This is obviously a significant change, and hence I wanted to run it by you first @tleunen. (Also, I changed the self to bind(this) as I went along, as I loathe the self = this pattern. It's not a deal-breaker though by any means)

[jjgonecrypto]

Ugh - this doesn't seem to be working. I'm still getting intermittent failures

[jjgonecrypto]

As mentioned in issue, it is due to this reality: browserify/factor-bundle#61

[tleunen]

Nice find. Hopefully you'll find a way to solve this

[jjgonecrypto]

This is one solution, but requires modifying both factor-bundle to return the output streams and having grunt-browserify listen for them specifically (sub-optimal). browserify/factor-bundle#61 (comment)

What I'd prefer is to have factor-bundle inject the streams it has into the wrap part of the browserify pipeline, such that b.end would only emit when the common and ALL the factor-bundles are complete, but as I mentioned there, I'm struggling to understand how do do that.