JVMCBC-74: Upgrade RxJava to 1.0.1 GA

Motivation
----------
RxJava just released 1.0.1 GA, and since this codebase was on release
candidates before this commit makes sure to run the latest version
possible.

Result
------
Depending on RxJava 1.0.1 GA

Change-Id: I9f77757f9fe22080941b5cd408497bc864ab7e5b
Reviewed-on: http://review.couchbase.org/43746
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>