Fixes logic for potential seed count / quorumSize
This closes #88
Support for cassandra v2 and vnodes

- adds USE_VNODES config for v1.2 and v2
- adds numTokensPerNode config
- adds checkForAndInstllJava7or8
- make AstyanaxSupport more robust for testing
Adds JmxHelper.terminate()

- important for entity stop(), if a connect attempt is taking a very
  long time to timeout and there are other jobs backing up.
PR #81: incorporate code review comments

- fix logging in CassandraDatacenterImpl
- fix CassandraNodeImpl.getTokens
- AstyanaxSupport: make keyspace name configurable, and better
  handle writeData failures when retries enabled.
- fix CassandraDatacenterLiveTest for v2: don’t explicitly set
  the JAVA_HOME
- add javadoc to MathPredicates.
This closes #81
use felix instead of osgi (as the signature of BundleWire called from BundleRevisionDependencies is different otherwise)
improve startup logging, mainly saying where persistence is being done for reference,
and moving OSGi timing to debug
some more tidying following emergency fix in https://github.com/apache/incubator-brooklyn/commit/bf627f76a7ad959a3beb7095e409a90e4cfa6e06
This closes #106
This closes #109
prototype of service_up being derived from service_not_up_indicators
add WhenFunctions which allows `Functionals.when(false).value("F")` approach to building up functions
add a new "updatingMap" enricher which helps when multiple enrichers contribute to a map, and use it for the new chaining of service_up behaviour
improve generics in the Enrichers.updatingMap(...) builder, and hints for how to do it for others