[ab] Fast pixel access

[Anthony Fairchild]

Hey Luke,

With your changes the rotations are now blazing fast!  I'm using the
ready/write generator functions.  Very cool, thank you for adding it.

So in about a week I will have more time to work on my game.   I will
also have a little bit of time I can spend on contributing to the
project if you guys are interested.  I've been coding in Lisp for just
about 2 years and have 12 years programming experience with
c/c++/java/python/ruby.  I own lispworks professional in case that
helps.  So let me know if there is anything I can do to help.

Anthony