ProxyManager refactoring
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
Currently proxy manager requires proxies to be registered under groups with names. Plus the proxy manager keeps a strong reference the registered proxy. This registration with the proxy manager is a chore and makes it confusing for cleanup etc.
A possible solution is to get rid of registration altogether. Every proxy just has a "flag" telling if it is 'UserLevel' -- meaning visible to the GUI or internal. The Qt client/python client etc all monitor UserLevel proxies. Proxy manager will always provide a mechanism to access any existing proxy (thanks to GUID). Thus proxy manager has no strong references to any proxy.