Improved callback logic. Simplified lwip driver.

include/Defs.hpp

@@ -39,6 +39,8 @@
 #include <sys/socket.h>
 #endif
 
+namespace ZeroTier {
+
 //////////////////////////////////////////////////////////////////////////////
 // Subset of: ZeroTierOne.h                                                 //
 // We redefine a few ZT structures here so that we don't need to drag the   //
@@ -208,4 +210,6 @@ struct zts_peer_list
 	unsigned long peerCount;
 };
 
+} // namespace ZeroTier
+
 #endif // _H