added SMOVE command to redis
added a is member of set command and an exists command
added unit testing for SMOVE, EXISTS and SISMEMBER commands
Merge pull request #139 from datacratic/redisSMOVE

added SMOVE command to redis
Merge branch 'master' into PLAT-355_s3-with-http-client
HttpRequest::Content no longer takes an tinyxml2::XMLDocument constructor