Jakob Theme

Hey, 

I don't know whether my changes are "deep" enough to treat this as a new prompt theme, but I just wanted to suggest it here. (my first pull request!)

It's basically `prompt_sorin_theme` with only slight modifications, mainly the `pwd` part moved to the right, I removed the `git` prefix to the `branch` segment, include `username`, remove two of the arrows and changed a few of the colours.

Actually, I would have liked to combine the path shortening mechanism of the `pwd segment` (`/u/s/l/bin` for `/usr/share/local/bin/`) with the `%~` function which represents named directories under their name and not their full path, but my script knowledge wasn't enough for that.

Best, Jakob

### Screenshots

![](http://i.imgur.com/0DRzliX.png)

![](http://i.imgur.com/9rd8SQe.png)