Minor tweak to BHandler::UnlockLooper()

Added calls to _init_message_(), _delete_message_(), and
_msg_cache_cleanup() to InitTerminateLibBe.cpp
Finished first implementation of BMessage::SendReply(), BMessage::_send_(),
and BMessage::_send_message()
Add BMessage to app.src, removed BBlockCache from support.src.
New BMessage::Private class has functions for twiddling BMessage internals


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@4371 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/os/app/Message.h

@@ -292,11 +292,14 @@ virtual				~BMessage();
 		float		FindFloat(const char *, int32 n = 0) const;
 		double		FindDouble(const char *, int32 n = 0) const;
 
+		class Private;
+
 private:
 
 friend class	BMessageQueue;
 friend class	BMessenger;
 friend class	BApplication;
+friend class	Private;
 
 friend			void		_msg_cache_cleanup_();
 friend			BMessage 	*_reconstruct_msg_(uint32,uint32,uint32);