ports/71221: new port: science/buddy - A Binary Decision Diagram library

[Li-Lun Wang (Leland Wang)]

I think math will be a more appropriate category than science, for BDD
is a diagram for logic decision.

-- 
 /-------\      /-\     /--------\
 \--\ /--/      | |     \--\ /---/
    | |    /----/ \----\/--/ \---\
  /-/ \-\  \----/ /----/\--\ /---/
  \-\ /-/      /  \     /--/ \---\
    | |       / /\ \    \--\ /---/ /\
/---/ \---\/-/ /  \ \---\  | \----/ |
\---------/\--/    \----/  \--------/
  e-mail address: llwang at infor.org