Adjusting the setup section of the tooling guide and the index page for tooling
Adding some of the third tooling section
Adding the final section of tooling section
Merge branch 'master' of github.com:google/WebFundamentals

* 'master' of github.com:google/WebFundamentals:
  Pass through HTML entities
  added notes about short links, no content was changed.
  Fixed title case, added line breaks, added collection, updated updated_on, minor image updates.
  Added line breaks, changed image to separate screen shots and better layout for images.