angular/angular.js — pull request #2105 by CaioToOn (2013-03-06 14:43:59+00:00)
Title: fix($http): ensure case-insens. header overriding

If user send content-type header, both content-type and default
Content-Type headers were sent. Now default header overriding is
case-insensitive.

As per [RFC 2616](http://www.ietf.org/rfc/rfc2616.txt), "[header] Field
names are case-insensitive".