documentcloud/underscore — pull request #774 by ryanve (2012-09-14 10:05:59+00:00)
Title: optimize _.mixin and _.wrap

push.apply is faster than slice/unshift or slice/concat. see [push-apply-ftw](http://jsperf.com/push-apply-ftw) and [underscore-wrap](http://jsperf.com/underscore-wrap).