compare resulting data in jsonify test
refactor #as_liquid
reduce nesting of #as_liquid
add in page nav to troubleshooting file
update site dir readme

Add some helpful info to the readme.
further clarify local dev steps
Jekyll-jalali plugin added to the plugins list.
modify as_liquid to use case statement
Merge pull request #3158 from afeld/as-liquid-refactor
Update history to reflect merge of #3158 [ci skip]
Merge pull request #3198 from mehdisadeghi/master
Update history to reflect merge of #3198 [ci skip]
use rake instructions instead
Merge pull request #3196 from jekyll/site-troubleshooting-updates
Update history to reflect merge of #3196 [ci skip]