Stop processing messages on full send buffer and dont disconnect.

Also decrease default send/receive buffer sizes from 10 to 5 mb
as this patch makes it easy for a node to fill both instead of
only send.

src/net.cpp

@@ -922,11 +922,8 @@ void ThreadSocketHandler2(void* parg)
                                 pnode->CloseSocketDisconnect();
                             }
                         }
-                        if (vSend.size() > SendBufferSize()) {
-                            if (!pnode->fDisconnect)
-                                printf("socket send flood control disconnect (%d bytes)\n", vSend.size());
-                            pnode->CloseSocketDisconnect();
-                        }
+                        if (vSend.size() > SendBufferSize())
+                            printf("socket send buffer full warning (%d bytes)\n", vSend.size());
                     }
                 }
             }