Mongodb autodiscover

Added in the ability for the MongoDB plugin to autodiscover Mongo processes running on the box at the specified port (or 27017 by default). It assumes an identical setup for all the processes on the host (same user/pw, port, etc).
Added in a flag to set an automatic naming option, useful for autodiscovery. It uses the ['repl']['setName'] to get a name to use as part of the scheme. This might not be the best parameter to pull from, but it was unique in the environment I tested on, and matched what I was looking for. 

Both of these are optional flags, and the plugin works the same without.