Add table of contents to README
Add table of contents to README

The README has gotten quite large. Adding a table of contents might help, especially if you're just looking for the installation section. Generated using DocToc: https://github.com/thlorenz/doctoc
ndbroadbent/scm_breeze,ghthor/scm_breeze,scmbreeze/scm_breeze,ndbroadbent/scm_breeze,ghthor/scm_breeze,scmbreeze/scm_breeze