cc65's C64 runtime and ip65 call past the jump table: $E5B4 takes the first
key from the keyboard buffer (cgetc), $EA24 points USER at the colour RAM of
PNT's line (cursor positioning), and $ECF0 holds the low bytes of the screen
lines' addresses (ip65's VT100 code), as Mapping the Commodore 64 describes
them. vicii_init's work moves out of $E5A0-$E5C8 to free $E5B4, and on the
standard layout PNT and USER are worked out through the routine at $EA24.
