Sort records for correct true/false positives

fixes #45 
Since these throw on unsorted input now, you should note that in the comment.

What do you think about using jsdoc comments to document the API of functions? The JS style guide [encourages](https://google-styleguide.googlecode.com/svn/trunk/javascriptguide.xml?showone=Comments#Comments) this, and there are tools which will extract them into documentation pages.