A couple months ago I created a simple little API for making my life easier, reverting to previous versions due to bugs was becoming a problem so I opted to host it on GitHub, and now, a month later I think it's production ready as it currently sports the following features:
  1. Buttons!
  2. Rectangles!
  3. Lines!
  4. Progressbars!
…I apologise for just posting a link, but GitHub has much better formatting so please do spare a look at the readme there as it's much more in-depth of what's avalible:

https://github.com/lennyitb/LennyGUI