add generator that returns a stream of random bytes <-- useful for writing benchmarks that send very large blobs to the database, without needing to keep those blobs in memory
remove all old byte iterator-related classes that came from YCSB
add tests to workloads that check performance of operation generation. more specifically, that they can generate 1,000,000 operations in less than 10 seconds (very generous - they general take 1.5seconds on my laptop), because if they take longer it is likely a bug
add method to TestUtils to support above mentioned tests
modify GeneratorFactory to give every instantiated generator the SAME random number generator instance, rather than creating one each. the reason is some workloads generate 1+ generators per operation, and random number generator instantiation turns out to be costly