Docset for GLFW

GLFW does not have an icon, so I did not include one in the docset.

**Note:** this replaces my previous, failed pull request: [#200](https://github.com/Kapeli/Dash-User-Contributions/pull/200).

I updated docset.json to include the author info and cleaned up GLFW.tgz so that it only includes the docset.