Update news with API incompatible changes.

And add a method overload to keep the number of API breakages down to 2!

Fix incorrect downsampling unit

The bug incorrectly assumed the downsampling unit was second while computing
start and end time of HBase scan.
- Fixed the math.
- Suffixed the field name with _ms.
- Added unit tests to address the bug.
  * downsample and downsampleMilliseconds.
- Added a nested helper class for unit tests to access private methods.
- Factored out the unit tests related to downsampling from the huge
  TestTsdbQuery.java. It was too big for Eclipse to run.

Signed-off-by: Chris Larsen <clarsen@euphoriaaudio.com>

Fix TestPutRpc unit tests to look for string in the JSON and avoid po…

…tential

problems with unknown field ordering.

Signed-off-by: Chris Larsen <clarsen@euphoriaaudio.com>

Update NEWS for v2.0.0 RC1

Update AUTHORS and THANKS.

Add a bit of README and some NEWS.

Change-Id: Ic2bd5f3f1946edbe148a8b15165861a561013f5e