[ab] Anthony's rotation function

[Justin Heyes-Jones]

Hi Luke

I grabbed the latest and did a clean up and ran it.

I get errors with most of the examples I've tried, mostly this one...

Undefined function LISPBUILDER-SDL:WRITE-PIXEL called with arguments (0
                                                                      0

#<LISPBUILDER-SDL:COLOR 2068461C>).
   [Condition of type UNDEFINED-FUNCTION]


bmp_sample returns

The slot LISPBUILDER-SDL::WIDTH is missing from
#<LISPBUILDER-SDL::SURFACE 206BA374> (of class #<STANDARD-CLASS LISPB$
   [Condition of type CONDITIONS::SLOT-MISSING-ERROR]



mixer.lisp seems to be working