Summary of what this does at the start of the README

It's probably a bit nitpicky, but I would love if instead of starting the README with the Usage instructions, there was an initial section that described what AppAssessment does, who might want to use it and why someone might want to use it. I realize that if you scroll down and click on the image of the `Summary Table' you can find this out, but it would be nice to know at the start of the document.