[Beta Enhancement] Added Opacity control to background rotator

This is a kind of roughly made system to change the level of opacity on the background. It does work there are just some things that I wasn't able to do. Each commit that I have made I have tried to talk about everything I did and what I couldn't do and why I did it that certain way.

I am still trying to learn Angular and Javascript and this is helping a lot. Thanks for the great app.

Rough list of things to do
* Add in dynamic highlighting of buttons depending setting selected
* Fix the 'Current Opacity' label to actually display the current opacity
* Find out a way to maybe not use letters as variables and,
* not use letters to select the CSS rule