advanced support of CQL3 Sampler
add logging for create/delete instance in pool
add hardcoded option MAX_ONLINE_TASKS=64 (per-sampler-thread)
add option ConsistencyLevel
replaced shared queue between callbacks and sampler threads to ThreadLocal CLQ and ThreadLocal AtomicInteger counters
fix many memory leaks
show query in SampleResult
remove poolTimeout option (CQL3/Put/Get samplers)
fix ByteBuffer leak (queryBB)
add exceptions on callbacks