Backport binary tarball assembly from 2.1 branch.
Add test for token map initialization at startup (JAVA-415).
Test connection release on ResultSetFuture#cancel (JAVA-407).
Add test for JAVA-418.
Update tests for balanced multi-dc tokens.

See pcmanus/ccm@bea312d
Merge branch '2.0' into 2.1
Bump C* test version to 2.1.0-rc6.