CHANGES

 o new functions `mk_exists` and `mk_forall` for quantifier elimination
 o new function `print` to print a BDD as nested "if..then..else"
 o new function `print_compact` to print a BDD in a compact form using
   conjunction and disjunction when possible, and falling back to
   "if..then..else" otherwise
 o new function `extract_known_values` to retrieve from a bdd the set of
   variables whose Boolean value is entailed by the bdd.
 o new function `count_sat_int`

November 13, 2018 (VERSION 0.4)
-------------------------------
 o no more set_max_var -> a functor Make and a function 'make' instead
 o new function restrict
 o new functions constrain and restriction
 o extend print_to_dot and display with optional print_var argument
All this contributed by Timothy Bourke (tbrk@github)

February 2, 2010 (version 0.3)
------------------------------
 o new function random_sat
 o new example in tiling.ml (tiling the 8x8 chessboard with 2x1 dominoes *)
 o init removed and subsumed by set_max_var
 o improved efficiency (one node table for each variable)

July 16, 2009 (version 0.2)
---------------------------
 o fixed bug in count_sat (unused variables below the top variable where not
   taken into account)

June 7, 2008 (version 0.1)
--------------------------
 o LGPL license, with special exception for linking (see LICENSE)