Add new connection type 'piplate' to the hd44780 driver (by J. Brogdon).

In the documentation replace the list of the connection types for hd44780
driver with the table also used in the configuration options description
(use only a single place to list and link everyting). While there, remove the
assembly code for lcdserializer.

server/drivers/hd44780-low.h

@@ -54,6 +54,7 @@
 #define HD44780_CT_USBTINY		20
 #define HD44780_CT_USB4ALL		21
 #define HD44780_CT_RASPBERRYPI		22
+#define HD44780_CT_PIPLATE		23
 /**@}*/
 
 /** \name Symbolic names for interface types