Setup Script

I wanted to learn more about bash scripting and expand my knowledge, so I made a Gitweb Theme Setup Script! There might be errors, or better ways to do things, but it works for me. Use it if you want to, merge it into your project, or don't. I won't be offended, just thought I would share.

This is my first ever real pull request to try and contribute, so sorry if I did something wrong.

Cheers!