preliminary group targeting functionality.

Can use multiple targets and it will give you the overlapping
percentage of the group.
group targeting complete.

Barring any bugs, group targeting functionality is completed.
Comments for readability
Update Readme for Group functionality.
Optimization

Changing some iterators to go over integers rather than indexes. Saves
space.
Fixed Logic Error in Group Probability

Taking into account  0 Success == Any Amount of Failure.
Removed Debug Print Statements

Whoops, left those in.
Merge branch 'group-targeting'