Fixed spacing to be consistent with Eiffel style guide
Changed test_make_empty and test_make_filled to use local checks (assertions)
instead of postconditions on global variables. This helps make the tests
more independent and atomic
Changed use of class attributes in  make_from_special, @ and put to use
checks on local members
More refactoring with check assertions. Added TODOs for boolean tests
Extracted all features dealing with printing into separate utilities
class. Removed conditional logic from many tests and added check
assertions.