JSHint cleanup
Fix module loading in IE11.

SC.Module was using a isIE check to determine how to detect when the script
finished loading. IE11 removed support for onreadystatechange, so the
module loaded callback was never called. Changed this to a feature detect
so it will always work properly.
Merge pull request #1114 from sproutcore/team/fairbanksg/ie11-module-load

Fixes SC.Module loading on IE11+