Creating test for some bug in serialization/unserialization
Allow log2m*regwidth to be small. Fix #2.

- Made paramter-min/max constants public.
- Added random elements to HllSerializationTest.
- Allow (de)serializers to work with small register values.
- Fix a bug in BitVector#registerIterator() when there was too much
  leftover space at the end of a word.
Version bump to 1.2.1.
Add new HLL constructor. Bump to 1.3.0. Fixes #3

- Add an HLL(log2m, regwidth) constructor that defaults to automatic
  EXPLICIT settings and using SPARSE.
Added release notes.
Fixed #4, lowered JDK requirement to 6 from 7. Version bumped to
1.4.0.
Make HLLs Cloneable. Fixes #5.
Add a maven dep snippet to the README.
Merge pull request #6 from blinsay/pull_request_5

Make HLLs Cloneable. Fixes #5.
Added reminder comment. No logic changed.
Version bumped to 1.5.0