Added PortMessage::ReadString and PortLink::AttachString to support BSession-style string attachments

Tweaks to startup code for BApplication
Tweaked PortQueue to utilize the BSession workaround for PortMessages
Tweaks to message protocol for BCursor


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@4939 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/kits/app/PortQueue.cpp

@@ -76,7 +76,7 @@ void PortQueue::GetMessagesFromPort(bool wait_for_messages)
 				delete msg;
 				break;
 			}
-			
+			msg->BSessionWorkaround();
 			_q.push(msg);
 		}
 		
@@ -90,6 +90,7 @@ PortMessage *PortQueue::GetMessageFromQueue(void)
 
 	PortMessage *msg=_q.front();
 	_q.pop();
+	msg->BSessionWorkaround();
 	return msg;
 }