Modification to the testCutIntro script

The calls were simplified and the logging is now
concentrated in one place.
Organizing cut-introduction code

The actual code that executes the cut-introduction
algorithm is inside private methods and three
public methods were created, one for each case:
- one_cut_one_quantifier
- one_cut_many_quantifiers
- many_cuts_one_quantifier

The object NCutIntroduction was deleted and its
methods were moved to CutIntroduction.