BoolStuff is a small C++ library that supports a few operations on
boolean expression binary trees. The main features are:
 - a boolean expression parser (supports operators AND, OR
   and NOT, as well as parentheses);
 - an algorithm to convert a boolean expression binary tree
   into its Disjunctive Normal Form;
 - a function that determines if an expression tree is in DNF.

A command named `booldnf' that calls this library is also provided.
