Improvements in CycleCanceling.

Main changes:
- Use function parameter instead of #define commands to select negative
cycle detection method.
- Change the name of private members to start with "_".
- Change the name of function parameters not to start with "_".
- Remove unnecessary documentation for private members.
- Doc improvements.

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

#undef HAVE_CPLEX

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

#undef HAVE_GLPK