A basic MongoDB 2.2.2 entity

* Runs on localhost and given port
* Accepts server configuration file
* Test confirms client can read and write data
README written by @richardcloudsoft
Correct type of DEFAULT_LOCATIONS in SingleWebServerExample
Use port and bind_ip arguments when starting MongoDb server
Adds several attributes to MongoDbServer

* Core is STATUS attribute, contains map of others.
* Uptime
* Operation counter
* Network bytes in/out/requests
Addresses review comments from @aledsage
Merge pull request #434 from sjcorbett/mongodb

Basic MongoDb entity