Provides the tools/bin/generate-tokens script that can be used to pregenerate allocation strategy tokens.
Refactors TokenAllocation for extensibility (and better re-use between strategies), and adds OfflineTokenAllocator.
TokenMetadata now has a configurable snitch (instead of hardcoded to DatabaseDescriptor.getEndpointSnitch()) for testability.
Adds logging of growth and stddev changes to allocate_tokens_for_local_replication_factor usages.
patch by Mick Semb Wever; reviewed by Paul Motta, Ekaterina Dimitrova for CASSANDRA-16205
Sam Tunnicliffe