This makes is slightly easier to use as you do not actually have to
construct the DataSetBuilder object but just call its static method.
The DataSetBuilderExplicitIterative methods are not static because they
use state of the builder object to create the data.
1. Additional ASSERT calls to validate arguments in: DataSetBuilderRegular
2. Fix some untested compile errors in DataSetBuilderRectilinear
3. Added a new unit test, cont/testing/UnitTestDataSetBuilderRectilinear.cxx
4. Provided additional tests for UnitTestDataSetBuilderRegular.cxx.
The new tests in (4) were also included in (3), and provide a much more robust way of validating datasets created. It has nested for loops to do an all-all test on various ways to specify the X,Y, and Z coordinates. It computes the bounds on the coordinate system and make sure they are correct.
Note: The GetBounds() call for Rectilinear is not working, and is an item for future discussion. It is disabled for now.
