changed package name to prototype
Created MinMaxPair class and test (for constructor)
passed constructor test
Added Rule class and test
Will hold a rule to apply to account codes
Added functionality to store inclusions/exclusions
these are based on min/max account code ranges, stored as lists
Added test suite
Added test for multi inclusion addition
Code+test disallowing creation w 0/negative ints
Code to prevent adding incl/excl that clashes with existing ones
Refactored clash test to remove some duplication