Change icon handling and charmaps:

* The full block icon now has index 0 and the heart has index 7. This makes
  the full block work if vBar custom chars are loaded (which use index 1-7).
* Prevent (hbar, vbar, bignum) modes from overwriting custom chars (except
  full block).
* Prevent the heartbeat from overwriting custom chars in vbar and bignum mode.
* Make the driver point to 0x1A and 0x1B characters for right/left arrow
  characters (those are the codes from HD44780 A02) and make all charmaps
  pointing to the correct characters.
* It is now possible to map the tilde character.
* Update other drivers that use hd44780-charmap.h (IOWarrior and ula200).
* Replace characters using charmaps on input instead of output!
* Remove some unnecessary comments.

server/drivers/lcd.h

@@ -107,12 +107,12 @@
 
 /* Type of characters currently stored in CGRAM. */
 typedef enum {
-	standard,		/* only char 0 is used for heartbeat */
+	standard,		/* one char is used for heartbeat */
 	vbar,			/* vertical bars */
 	hbar,			/* horizontal bars */
+	icons,			/* standard icons */
 	custom,			/* custom settings */
 	bignum,			/* big numbers */
-	bigchar			/* big characters */
 } CGmode;
 
 /* What does the shared module handle look like on the current platform? */