add in page nav to troubleshooting file
update site dir readme

Add some helpful info to the readme.
further clarify local dev steps
use rake instructions instead
Merge pull request #3196 from jekyll/site-troubleshooting-updates
Update history to reflect merge of #3196 [ci skip]
Add appveyor configuration YAML.
Tweak appveyor.yml.
Tests should run now.
README.markdown: Add AppVeyor badge.