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-piplate.h

@@ -0,0 +1,9 @@
+#ifndef HD_PIPLATE_H
+#define HD_PIPLATE_H
+
+#include "lcd.h"		/* for Driver */
+
+/* initialise this particular driver */
+int hd_init_i2c_piplate(Driver *drvthis);
+
+#endif