Remove the default build directory from loader combo url

This removes the default `build` directory from Loader generated combo URL's.

Based on this [thread](https://groups.google.com/forum/#!msg/yui-contrib/PJRWTP_OOtM/YTUHfGrA8O8J) and this [fiddle](http://jsfiddle.net/davglass/XkfWY/).

This also updates a test that now contains one less URL than before.

*Seed and Loader build required to test*