version 0.66 (July 2020)
-remove GPW solver, as it was removed from TTT2
-fixed correct linking of num library

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version 0.4beta (February 2012)
-use unsatisfiable core of SAT solver to
  -determine unsatisfiability
  -incrementally increase bits

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version 0.3 (March 2010)
-added simple heuristics to choose bits

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version 0.2 (January 2010)
-added back-end via bit-vector arithmetic

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version 0.1 (September 2009)
-initial version