Change to support multiple versions of the same client bundle installed

on in the framework.

During initialization, the aggregator creates a working directory for the dependency map and cache.  The directory location is qualified using the bundle id of the contributing bundle (the bundle that instantiated the aggregator), and any directories specifying other bundle ids for the same bundle name are deleted.  This prevents multiple versions of the same bundle from co-existing in the same framework.  

With this change, the directories for any bundle ids that are still installed in the framework are preserved when cleaning up a bundle's working directory.