Support Stream Mode

I could not get streaming to work using the [tar-stream](https://github.com/mafintosh/tar-stream) package. I switched it out for the [archiver](https://github.com/ctalkington/node-archiver) package. I hope that is alright. Archiver seems to be more flexible when adding files to the pack.

Added tests to test.js and gulpfile.js as well. Removed failing test from previous pull request.