Squashed 'vendor/jslint/' changes from 9a1697c..abc0d34

abc0d34 assignment expressions
85ea659 warn
f300f17 Object.create(null)
a16c7ae init & used
68e5657 remove option.undef
1f18209 - 1
b9b487f yellow

git-subtree-dir: vendor/jslint
git-subtree-split: abc0d34007353642b8a4a822627549c459070f8b
Update JSLint
Fix tests for JSLint 2013-05-01