fix Segmentation fault caused by passing NULL as return value
add __str__ for _Varstraints consisting of self._unique_id and self.name()
add GLPK_version function to allow getting GLPK version as a string
hide parameter dicts from python interface
numbers.Integral instead of numbers.Integer, and fix Variable.bounds() integrality test
use 'from x import y' format
whitespace normalization
add bindings for CNF-SAT basedf integer feasibility solver