Renamed plugins to fit new url
Renamed melanie to melanee
Preferences can now be set to empty string for extension points without
any registered extension.
Added extension point etc. for validation service.
Changed constant to OCL implementation.
Renamed proximity indication service to designation service.
Renamed preference constant from proximity indication to designation
Added application visualization service to preferences and to extension
point service
Updated default value for appdsl visualizer preference.
seperated validation and constraint language service
Merge branch 'master' of c:/w/m/old