Adding screenshots and updating readme to link to themes

README.md

@@ -42,6 +42,8 @@ Anything in the custom directory will be ignored, with the exception of `custom/
 
 There are a few bash it themes.  If you've created your own custom prompts, I'd love it if you shared with everyone else!  Just submit a Pull Request to me (revans).
 
+You can see the themes available [here](https://github.com/revans/bash-it/wiki/Themes)
+
 ## Help out
 
 I think everyone has their own custom scripts accumulated over time.  And so, following in the footsteps of oh-my-zsh, bash it is a framework for easily customizing your bash shell. Everyone's got a custom toolbox, so let's start making them even better, **as a community!**