Added RangeTestHelper
buildfile: Switched spec to brief summary

The tests are getting numerous, and the output is getting verbose.
Generator: Using lambda instead of anonymous class

Of course! The hat goes on the head!
Renamed MultiRangeTest

MultiRangeTest was already (accidentally) renamed to
MultiRangeMismatchTest in a previous commit. Now also removed two of
the tests.
SingleAndMultiRangeNextTest: examine space.next

Compares produced and expected values for various parameters.