Rearrange the channel buffer sizes into three neat use-editable values in

options.h. Increasing RECV_MAX_WINDOW gives big network performance
increases - even with the present buffers (which haven't changed) it
performs a lot better.
Next step is to make the window size a cmdline option.

--HG--
extra : convert_revision : 24c7cb47fb56cf5b82e3bc0859b45ea83038eab0

channel.h

@@ -45,16 +45,8 @@
 /* Not a real type */
 #define SSH_OPEN_IN_PROGRESS					99
 
-#define MAX_CHANNELS 100 /* simple mem restriction, includes each tcp/x11
-							connection, so can't be _too_ small */
-
 #define CHAN_EXTEND_SIZE 3 /* how many extra slots to add when we need more */
 
-#define RECV_MAXWINDOW 8000 /* tweak */
-#define RECV_WINDOWEXTEND 1000 /* We send a "window extend" every
-								RECV_WINDOWEXTEND bytes */
-#define RECV_MAXPACKET RECV_MAXWINDOW /* tweak */
-
 struct ChanType;
 
 struct Channel {