Javascript utility to invoke (remote) sharding setups, dynamically modify.

The overall structure to the project is:

shard_setup.js -> Service and ShardedSetup objects, allows you to transparently set up a sharded mongodb configuration with configurable:
	- mongos frontends
	- named shards as replica sets
	- replicas per shard
	- host types and options (local and remote via ssh)
		- ssh works(ed), local is the most up-to-date at the second
	- service layouts (i.e. mapping of mongo services to hosts)
	
shard_setup_local.js -> Local host plugin
shard_setup_ssh.js -> SSH host plugin

Right now the host connectivity is a bit rough-and-ready, as the mongo shell makes it hard to cleanly launch the processes by using various shell utilities (and the mongo processes themselves do not record much useful local process info).

The idea is to launch a sharded configuration by invoking:

2 shards, default of three replica nodes per shard
> var ss = new ShardedSetup({ mongos : 1, shards : 2 })

2 shards, 1, 2, and 3 replica nodes per shard 
> var ss = new ShardedSetup({ mongos : 1, shards : [1, 2, 3] })

3 shards, 1, 2, and 3 replica nodes per shard (shard names a, b, c)
> var ss = new ShardedSetup({ mongos : 1, shards : { a : 1, b : 2, c : 3} })

3 shards, 1, 2, and 3 replica nodes per shard
> var ss = new ShardedSetup({ mongos : 1, shards : 3, replicas : [ 1, 2, 3 ] })

3 shards, 1, 2, and 3 replica nodes per shard, arbiter as one node
> var ss = new ShardedSetup({ mongos : 2, shards : 3, replicas : [ 1, 2, [ null, null, "$arbiter" ] ] })

3 shards, 1, 2, and 3 replica nodes per shard, arbiter as one node, named mongoses
> var ss = new ShardedSetup({ mongos : ["alpha", "beta", "gamma"], shards : 3, replicas : [ 1, 2, [ null, null, "$arbiter" ] ] })

3 shards, 1, 2, and 3 replica nodes per shard, arbiter as one node, named mongoses, two hosts
> var ss = new ShardedSetup({ mongos : ["alpha", "beta", "gamma"], shards : 3, replicas : [ 1, 2, [ null, null, "$arbiter" ] ], hosts : [ "ssh://[email protected]", "ssh://[email protected]" ] })

3 shards, 1, 2, and 3 replica nodes per shard, arbiter as one node, named mongoses, two hosts, random layout (places services on hosts)
> var ss = new ShardedSetup({ mongos : ["alpha", "beta", "gamma"], shards : 3, replicas : [ 1, 2, [ null, null, "$arbiter" ] ], hosts : [ "ssh://[email protected]", "ssh://[email protected]" ], layout : "default" })

Only have a default layout for now, basically assigns services to hosts in-order with wrapping.  

ss.init() starts the services on hosts, assigns some useful shortcuts for connections to each host

ss.$active() = connection to first active mongos
ss.$mongos$[name|#] = connection to mongos
ss.$shard$[name|#] = connection to shard replica set
ss.$replica$[name|#]$[replica #] = connection to replica in set (slaveok'd)

ss.end() stops all services