Add multi-shard shardDefinition to PrimeFactorsIndex.
Add multi-shard shardDefinition to PrimeFactorsIndex.

danluu/BitFunnel,danluu/BitFunnel,danluu/BitFunnel,BitFunnel/BitFunnel,BitFunnel/BitFunnel,BitFunnel/BitFunnel,BitFunnel/BitFunnel,danluu/BitFunnel,BitFunnel/BitFunnel,danluu/BitFunnel,BitFunnel/BitFunnel,danluu/BitFunnel