* 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.