Update README.md - Githubissues

Motivation

Update appearance of readme, add simple table of contents at the top linking to important sections

[ ] Have you ensured the PR description clearly describes the problem and solutions?
[ ] Have you checked to ensure that there aren't other open or previously closed Pull Requests for the same change?
[ ] If this PR fixes an issue, is the first line of the PR description fix #XX where XX is the issue number?