Merge pull request #94 from chafnan/master

Added check to find phantomjs in the path before looking in the module path. Fixes #92.
Do not ignore things that should be in your global ignore.
Note 3.1.3 change log.
Prepare for 3.1.3 release.
Small comment cleanup.
Test with Chai.js v1.8.x
Test with Mocha.js v1.13.x
Merge remote-tracking branch 'upstream/master'