Bash PS1 Colors and More Space

Below is a script I use for adding some jazz and meta information to my prompt in bash. Although I do use oh-my-zsh now-a-days, a nice Bash prompt is still useful when I am on a server without zshell.

I'm not sure if this is best way to achieve this, but I use `echo` in order to add the color variables in the PS1 string, which should be evaluated only per PS1, not at the time of definition. I originally was using double quotes to surround the entire thing, but then realized that `git_ps1` was getting executed only when PS1 was being defined, instead of when PS1 was being evaluated.

On most systems, you can save this script at /etc/profile.d/prompt.sh and it will be automatically evaluated. If you do set your PS1 using oh-my-zsh, then whatever value was set here will be overridden.