Add documentation on element status lights
Add note about the 3 connecting phases looping
Shortening text
Merge pull request #21 from helium/adt-element-lights

Add some documentation on the element lights

I tweaked some things and committed them back to the branch but this is good to go. I'm merging. Thanks, @Vagabond. 

@PeterMain Is there a chance you could tweak the LED table a bit? It's looking a bit jumbled.
@amirhaleem Please redeploy when you get a moment.