replace jscoverage with istanbul
submit coverage to coveralls
ignore coverage dir
alphabetize devDependencies
exit prepublish script if tag not found
add 0.17.0 changelog
Update History.md

I spent to long trying to figure out how to get pretty print to work before realizing that it had been removed... This should avoid others making the same mistake.
Merge pull request #520 from gabrielf/patch-1

Update History.md
Merge pull request #506 from cheeriojs/coveralls

Coveralls
Merge pull request #517 from cheeriojs/prepublish

exit prepublish script if tag not found
Added double quotes to radio attribute name to account for characters such as brackets