Switch from NetWrap to net_hi (allow more than 2 player games)

src/net_hi.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include<stdbool.h>
+
+bool net_hi_request_peercode(void *ud, void(*callback)(void*, const char *peercode));
+bool net_hi_setup(bool host);
+void net_hi_update(double now);
+
+void net_hi_add_punch(const char *peercode);
+
+bool net_hi_connect(const char *peercode);