All read/Cache write/Cache fields now padded.Int64

Previously these fields were plain int64 with the read, writeCache
adjacent and write, readCache adjacent in memory. This produced a slow
down, although it isn't completely clear why this occurs it is likely
related to excessive cache coherency traffic.
Adding performance tests for unsafe queues
Profiling  is now activated by the -profile flag

Previously every time we ran a performance test for the queue it
produced a profile file. This was a pain because we have to keep
deleting them.