Added check for null to avoid NullPointerExceptions when using the
ViewVisibilities-List
Changed Arguments in EAnnotationHelper to Default{Menu, View,
Coolbar}Visibility for more straightforward usability
Moved id-retrieval out of switch statement to improve readability and
compactness of the class
Fixed wrong URI for Annotations
Added an access rule and imported packages to make the
org.eclipse.ui.internal.* packages accessible from the plugin code
Added a PerspectiveListener to delegate the task of showing/hiding menus
depending on the shown perspective to it. Up to now, the manager shows
those menus specified in the visualizer, but still lacks the capability
to restore the default menus when switching back to the Melanee
perspective