stefanpenner/ember-cli — pull request #1952 by rwjblue (2014-09-10 01:19:57+00:00)
Title: Limit concurrent number of copy operations.

If the output directory contains more than 16 files (for example if you have merged in some fonts/themes/etc) you would get EMFILE errors due to the copy operation. This limits the concurrency when copying to 2.