Tests when `findWhere` can't find anything
add test case for _.intersection
Hint at array size in _.values.
Merge pull request #1227 from braddunbar/length-hint

Hint at array size in _.values.
Document `findWhere` when it can't find anything
Merge pull request #1228 from JensRantil/document-findWhere

`findWhere`: Improved documentation and tests (2nd)
Merge pull request #1204 from kbrainwave/master

add test case for _.intersection
Fixes #1199 -- Add an indexBy function to go with groupBy and countBy.
Merge branch 'master' of https://github.com/jashkenas/underscore
Fixes #1192 -- documentation clarification for isNaN
Fixes #1159. Document that 'negative' ranges are zero-length.