A couple of scripts were not Python 3 compatible. Update smtextgen to
use print() instead of bare print, and update the texture build script
to use the correct binary mode for writing binary files.
This is one of the screens of text shown between demos in the demo
loop. Generate this from the contents of a static text file. I
originally wanted to generate this programatically from the CREDITS
file but there are too many contributors to fit them all on the page.
Instead of generating text and image parts in separate stages, add
the ability to include an image in the smtextgen command line. This
makes the command line in the Makefile clearer.
The original Doom HELP screen showed the default key bindings for the
game's controls. This is not so useful nowadays: at worst it's
outright misleading because the player might not be using the
defaults, but it's also redundant because most modern source ports
allow the key bindings to be changed via the menus, which doubles as a
convenient list of the current key bindings.
Z0k suggested an alternative HELP screen that shows the items and
powerups available in the game. More discussion can be seen in this
thread: http://www.doomworld.com/vb/freedoom/69458-help/
