fix fqn() to also work for prefix
fix fqn() to also work for prefix

PDXostc/rvi_core,uwiger/rvi_core,magnusfeuer/rvi_core,magnusfeuer/rvi_core,uwiger/rvi_core,PDXostc/rvi_core,PDXostc/rvi_core,uwiger/rvi_core,magnusfeuer/rvi_core