adding support for alias when it comes to name bundles

This PR will help to mitigate the problem when big names are used for pkgs that might affect the performance of the YUI loader when it comes to produce combo urls.

For example, a url like this:

http://l.yimg.com/zz/combo?os/mit/td/td-applet-comics-0.0.43/td-applet-comics-templates-main/td-applet-comics-templates-main-min.js

could be optimized to something like this:

http://l.yimg.com/zz/combo?os/mit/td/td1-0.0.43/td1-templates-main/td1-comics-templates-main-min.js

this is specially useful for generated modules based on the name of the bundle.