Changeset 6998

#1672 Changed again how plugin discovery works because of Hive. The reason is that it must be possible to move the plugin and working directories away from the original slave working directory. This is needed for the Slave App and also in the future for the windows service because we don't want it to run as the LocalSystem user.
I have removed setting the PrivateBinPath and am now setting the ApplicationBase. This doesn't effect HL (because ApplicationBase is set by default to pluginDir anyway) but makes Hive work. The reason why setting the PrivateBinPath doesn't work with moving plugin and working directories is (from msdn): "Private assemblies are deployed in the same directory structure as the application. If the directories specified for PrivateBinPath are not under ApplicationBase, they are ignored."