#599 - bug fix for calling LookupTable on non-square arrays

This is a tiny pull request for the bug that @arunkannawadi found when calling LookupTables on arrays that are 2d but not square.

I also put this case into the unit tests in case any future changes to this class might break that functionality.

This was small enough that I wasn't even sure it needed a PR, but just in case, here it is.
These tests just check that no exception is thrown.  It looks like we don't anywhere test that the values come out right when the input is a 2-d array.  That would probably be worth adding as well.