Add TOC to README
Add TOC to README

Also add a few extra sections on Git and Vim integration.

Change-Id: I3f7790c7361710e7a7b6c034fe68cccfaa7d8904
Reviewed-on: http://gerrit.causes.com/40441
Tested-by: jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@causes.com>
Reviewed-by: Shane da Silva <67fb7bfe39f841b16a1f86d3928acc568d12c716@brigade.com>

skateman/haml-lint,mzp/haml-lint