Actual PHP RocksDB driver (from RocksServer)

• Moved actual PHP RocksDB driver (from RocksServer https://github.com/valmat/RocksServer)
• Added tests
• Added prefix iterator

Compatibility with the new version of PHP-CPP

• Compatibility with the new version of PHP-CPP
• mget now returns an iterable object. If you need an array as result of mget, there is a method mgetArray

First workable release

v0.1

some fixes