Allows life.py to use other characters for rendering (alphanumeric plus
punctuation characters), apart from the default asterisk "*". The
rendering character can be specified from the command line.

Summary: This patch makes a non-essential change to a curses demo.  It
also reverses several 2.x to 3.0 edits, turning it back to 2.x code.  So
the current version must be rejected.  Even if corrected, I would still
recommend closing.

To me, allowing any printable ascii char, even space, to represent live
cells adds nothing to the file's value as a curses demo.  Perhaps # as
an altnative, but even that would be a distraction from the main purpose.

The large bash-specific input chart is very nice.  I wish I has had
something like that when I worked with sh and csh.  But it has little to
do with this program in particular or Python as such and I think it
would be a distraction if added.

These diffs and others like them replace 3.0 code with 2.x code that in
two cases will not work in 3.0.

-            raise ValueError("Coordinates out of range %i,%i"% (y,x))
+            raise ValueError, "Coordinates out of range %i,%i"% (y,x)

-                live = (i,j) in self.state
+                live = self.state.has_key( (i,j) )

-    xpos, ypos = board.X//2, board.Y//2
+    xpos, ypos = board.X/2, board.Y/2

Thank you Terry. I highly appreciate your comments.

I agree with tjreedy that this change is not very interesting for a demo
program.  It would be more interesting to add larger features such as
different cellular automata, mouse or colour support, or something like
that.

Thanks for your patch, anyway.