Introduce a ring buffer implementation for server's network input. As a

result, clients are not disconnected due to sending large messages.

ChangeLog

@@ -20,6 +20,7 @@ v.0.5dev (ongoing development)
  + hd44780: Add a 'none' charmap which does not replace any character
  * hd44780: Change mapping for spanish 'n with tilde' characters
  * hd44780: Exclude pin for switchable backlight from keypad scanning
+ * server core: New network input buffering
 
 v0.5.3
  + lcdexec: notification when called program finishes