Added functions for utf8 and double types
Added functions for utf8 and double types

mongodb-labs/mongo-hhvm-driver-unsupported,110035/mongo-hhvm-driver,txg168/mongo-hhvm-driver,10gen-labs/mongo-hhvm-driver,apuckey/mongo-hhvm-driver,txg168/mongo-hhvm-driver,txg168/mongo-hhvm-driver,110035/mongo-hhvm-driver,apuckey/mongo-hhvm-driver,mongodb-labs/mongo-hhvm-driver-unsupported,10gen-labs/mongo-hhvm-driver,10gen-labs/mongo-hhvm-driver,apuckey/mongo-hhvm-driver,apuckey/mongo-hhvm-driver,mongodb-labs/mongo-hhvm-driver-unsupported,110035/mongo-hhvm-driver,110035/mongo-hhvm-driver