Moved the clipboard and server content updating to its own class

Updating the clipboard content and serer content happend in the
integration providers. It just doesn't belong there... so I moved
it to its own class.
Deprecated the clipboard content request methods
Added blocking get/set methods to the push and pull services
Renamed the onPulled method to onRemoteContentChange

When a class just needs the remote content it shoudn't use the
event because it is for sudden remote changes.
Put 'remote' in all the syncing get and set method names
Set the default state of the sync-clipboard binding true

Because this was null by default (and thus disabled) the autosyncing
didn't work.
Replaced the sync-clipboard binding calls to the blocking one's
Removed the useless onPushed listener callback
Removed the clipboard updater from the swt interface

Again this shoudn't happen in a user interface class. And this now
already happends in the sync-clipboard binding class.
The onContentSet method new gets called if the clipboard is updated
Renamed the onContentSet method to onClipboardContentChange
The sync manager nolonger needs the clipboard manager
Replaced the requestGet's with real content updating in the integrations
Removed the onContentGet and requestGet methods completely