modulePaths is not compatible with async=true

Hi,
When developing custom modules, we can now use the modulePaths attribute in the <dojo:header> tag to specify the module path.

However, this doesn't work if we try to switch to AMD mode by setting the attribute async="true" in <dojo:header>.

If I understood correctly the dojo loader documentation, we should use the "paths", "packages" or "packagePaths" attributes instead.

See http://dojotoolkit.org/reference-guide/loader/amd.html#configuration-variables