(#52) portal, testing: The page controller now handles visibility events to coordinate the visibility of widget controllers.
      The portal now provides the AngularJS axVisibilityService to inform directives about changes to their visibility.
      The portal also now provides the axHeartbeat service to register callbacks to run right after the next event-bus tick plus $apply.
Merge branch 'feature/52-manage-visibility-events--rebase-onto-59'

* feature/52-manage-visibility-events--rebase-onto-59:
  (#52) portal, testing: The page controller now handles visibility events to coordinate the visibility of widget controllers.
        The portal now provides the AngularJS axVisibilityService to inform directives about changes to their visibility.
        The portal also now provides the axHeartbeat service to register callbacks to run right after the next event-bus tick plus $apply.
(#60) fix phantomjs installation

Conflicts:
	CHANGELOG.md
Merge branch 'feature/60-fix-phantomjs-installation'

* feature/60-fix-phantomjs-installation:
  (#60) fix phantomjs installation
Fixed grunt-laxar version
(#61) added first profiling tools for scope property watchers.
Merge branch 'feature/61-implementing-watcher-profiling'
Added missing NEW FEATURE hint.
prepared artifact for upcoming release v0.14.0
(#62) fixed endless recursion on navigation when place and target have the same name.
Merge branch 'feature/62-fixing-endless-recursion-on-navigation'
(#63) axVisibilityService: use scope.$id to identify handlers, not scope.id
Merge branch 'feature/63-visibility-service-fix-id'

* feature/63-visibility-service-fix-id:
  (#63) axVisibilityService: use scope.$id to identify handlers, not scope.id
(#66) prevented endless navigation ping pong in flow controller.
Merge branch 'feature/66-preventing-endless-navigation-ping-pong'
(#65) fixed navigation being broken when parameter values were missing.
Merge branch 'feature/65-fixing-broken-navigation-for-missing-parameters'
(#67) re-added missing widget root element IDs
(#67) re-added missing widget root element IDs: changelog
Merge branch 'feature/67-fix-missing-dom-ids'

* feature/67-fix-missing-dom-ids:
  (#67) re-added missing widget root element IDs: changelog
  (#67) re-added missing widget root element IDs