stat: Locking during stats updating replaced with atomic update
stat: IO stats merged into global eblob stats
Merge pull request #60 from IIoTeP9HuY/io_stats

Synchronization mechanism in stats updating changed. IO stats merged into global stats.
Merge pull request #61 from IIoTeP9HuY/master

cmake: CMake Module to check platform atomic support added
stat: ifdef logic in atomic.h simplified