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/IOWarrior.c

@@ -1044,10 +1044,10 @@ static unsigned char block_filled[] =
       IOWarrior_chr(drvthis, x, y, 2);
       break;
     case ICON_ARROW_LEFT:
-      IOWarrior_chr(drvthis, x, y, 0x7F);
+      IOWarrior_chr(drvthis, x, y, 0x1B);
       break;
     case ICON_ARROW_RIGHT:
-      IOWarrior_chr(drvthis, x, y, 0x7E);
+      IOWarrior_chr(drvthis, x, y, 0x1A);
       break;
     case ICON_CHECKBOX_OFF:
       IOWarrior_set_char(drvthis, 3, checkbox_off);