Now it is ways better (it simply does `random number` modulo `screen rows`
- or columns, depends).
There also was an error in comparing snakeX,Y with new piece of food's X,Y
Now really fixed (I hope, at least, since the bug is terribly difficult to
reproduce)
Also improved printing routine: now it can print general hexadecimal numbers,
and can locate them everywhere across first line (and beyond also, since it
is not checked, but if you do, you are a moron). Simply put byte to be print
in accumulator, column in Y index, and then jsr.
the pseudo-random routine pseudo-randomly generated X,Y for new piece of food
that corresponded to immediately next snake head position.
This X,Y resulted empty when checked in the routine, but suddenly after it
is overwritten with snake head, so food simply disappears.
This leads to impossible game play, because no new pieces of food are
generated if no food is previously eaten, but there is no food to eat, so...
Hope to have fixed.
