make WinRandomAccessFile safe for multi-thread access; user QueryPerformanceCounter for NowMicros(); remove unused code
make WinRandomAccessFile safe for multi-thread access; user QueryPerformanceCounter for NowMicros(); remove unused code

zao/kkowalczyk-leveldb,LazyCodingCat/LevelDB,zao/kkowalczyk-leveldb,zao/kkowalczyk-leveldb,zao/kkowalczyk-leveldb,LazyCodingCat/LevelDB,LazyCodingCat/LevelDB,LazyCodingCat/LevelDB