Homepage cleanup for audit.

Homepage cleanup. Code looks good. Updated images to all be of the latest tools. Images figured, spans changed to kbd where appropriate, removed confusing links around images.

Hopefully this all works right, can't really test the index page locally. This is *mostly* just cleaning the code style up some. Minor grammar updates to drop some wordyness. And then ofc the updated images. Some are just renamed since I realized in looking things over I was being served incorrect images.

The biggest thing that could be off worry here is I dropped the breakpoint links. Since it isn't being produced anymore I don't really see mentioning it being a big thing for the homepage.
Nothing extra here and they shouldn't be spans. KBD is used to indicate keyboard input. When showing combinations you wrap the individual keys in its own input element. The [W3 Wiki](http://www.w3.org/wiki/HTML/Elements/kbd) has an example of this.

I would like to get rid of the class="kbd" entirely, but it appears the styling is attached to that last I saw.