cmakelists.txt initial commit
port* files initial commit
make it build on win32/win64, add env_win.cc (for now copy of env_posix.cc, does not compile)
env_win finished, untested
add tests, fix build problems, fix some bugs

- fix rename and fopen("rb") bugs
- fix getchildren path
- fix mmap move bug
added an intermediate winapi layer to capture RAII and other bugs
Mutex holding_thread_id restored after woken up in CondVar
use windows DeleteFile, allow all file sharing flags to pass tests
GetChildren doesn't return . and ..
cmakelist: install and test added
add winapi writeFile
solve windows db_test/MissingSSTFile problem, fix WinRandomAccessFile sharing

- modify db_test/MissingSSTFile because windows doesn't delete opened files
    (uses a backdoor for temporarily switching off memory-mapped files)
- fix WinRandomAccessFile in multithreading context (sharing issue)
snappy support and config file refactor
Workaround for corruption_test/Recovery to pass on Windows
Update README with info about this port (reason: github)
Merge from tamaskenez/leveldb_windows
Fix Windows build