Large cleanup:

- Removed hostname lookup (it blocks, and you can always do it yourself)
- Reorganized debug levels (after hints from Axel M�ller):
  0	Startup message and errors
  1	Connection logging
  2	Meta protocol information
  3	Verbose meta protocol (includes copy of transmitted requests)
  4	Packet information (logs transmission/errors of UDP packets)
  5	Verbose packet information (every single byte, not implemented yet
	to protect ourselves from filling up /var/log directories)
- Made log messages more consistent

src/net.h

@@ -104,7 +104,7 @@ typedef struct conn_list_t {
   ip_t vpn_ip;                     /* his vpn ip */
   ip_t vpn_mask;                   /* his vpn network address */
   ip_t real_ip;                    /* his real (internet) ip */
-  char *hostname;                  /* the hostname of its real ip */
+/*  char *hostname;                  /* the hostname of its real ip */
   short unsigned int port;         /* his portnumber */
   int flags;                       /* his flags */
   int socket;                      /* our udp vpn socket */