Removing manual tar handling.

Apparently Yeoman handles the TAR stuff on its own.

See [generator-firefox-os/db3bb9f7f904591e9b3b5409adc3fb96c9ecd601](https://github.com/zenorocha/generator-firefox-os/commit/db3bb9f7f904591e9b3b5409adc3fb96c9ecd601).
refs #2