Mon 23 Jan 2017 : suppressed a superfluous error message in poly.cpp
  and extra printing in dict.h when reading a polynomial system from file.

Sun 22 Jan 2017 : new test program test_poly.cpp, with a new makefile.

Sat 21 Jan 2017 : reformatted code of poly.h and poly.cpp.
  More reformatting in dict.h and polysol.cpp.
  Reformatting in linklist.h and linklist.tpp.

Thu 19 Jan 2017 : reformatted the code in utilities.cpp, utilities.h,
  and polysol.cpp.  More edits in poly.cpp.

Wed 18 Jan 2017 : reformatted code in poly.cpp.

Wed 19 Aug 2015 : reformatted polysol.h, made deletion mute,
  also muted deletion of polynomial system in poly.h.

Mon 17 Aug 2015 : upgrade code with new versions, and new polysol.h
  and polysol.cpp, updated with change_sol() method.

Fri 7 Aug 2015 : added change_sol method to PolySolSet class in poly.h,
  defined by the code in poly.cpp.
