Add packages directory to ignored paths/files
Make calculate method an instance method. This is the normal pattern to increase testability and is more typical for C# classes.
Simplify array constructors and remove temporary variables  to increase readability. They should optimize the same way regardless.
Simplified conditional logic in options handling for interactive mode.
Added generator implementation.
I/O handlers should accept the more generic IEnumerable<BigInteger> rather than the specific array.
Add ability to specify generator solution and acceptance test using generator.
Merge branch 'develop'