Additional methods to IntegerSet

Made a few methods to make IntegerSet work in a more math like fashion.
Included new methods of:
* union
* intersection
* difference
 that take two IntegerSets and produce a third rather than alter the
original.
Added a Vector class
Added  a Vector class, edited the SetTools class

In the SetTools class I completed the nSetMaker method
I have included a Vector class so that we can compute spectrums.