Expose underlying Asset source in the individual API's

In some cases it is interesting to get the 'real source' of an Asset beyond the InputStream. Where on disk is the FileAsset read from?

Both for Tooling integration and e.g. the JRebel Arquillian extension it is needed to know where a source came from to do the linking.

File FileAsset.getFile
String ClassLoaderAsset.getResource
Class<?> ClassAsset.getClass

etc