Add generators for series, add initial test for hasValue
Add tests for Series.hasValues; Fix bug therein
Weight (Value, NA, NM) to (9, 1, 0) for sparse and (7, 2, 1) for dirty columns and sequences
Remove collect from Series.hasValues test
Refactor ReducerPropSpec to use SeriesGenerators
Switch to using arbitrary and suchThat rather than specialized generators
Create case classes to use specialized implicit generators
Tidy up docs
Merge ReducerPropSpec into ReducerSpec
Fix Double precision issue in tests
Merge pull request #31 from mrvisser/topic/series-tests

Fix Series.hasValues, add test coverage