Added the function isFinite(), and replaced the calls to finite() with it.
This was necessary because finite() is not a standard function. Neither can
we use its standard counterpart isfinite(), because it was introduced only
in C99, and therefore it is not supplied by all C++ implementations.

/* Define to 1 if you have CPLEX. */

#undef HAVE_CPLEX

/* Define to 1 if you have GLPK. */

#undef HAVE_GLPK