Add proxy support.
change how the datacenter is found

Instead of using serviceInstance.find_datacenter to find the datacenter by name, loop through rootFolder.children looking for a child that has that name and is a datacenter.
The reason to do this is that rootFolder.children is populated with the children that the user has permissions to see. serviceInstance.find_datacenter does rootFolder.traverse which requires the permission to search through all the children
added command vm move
Merge pull request #75 from CoreMedia/master

added command to get the datastore with the most free space
Merge pull request #70 from RallySoftware/master

added command vm move
Merge pull request #69 from b-dean/find_datacenter_without_traverse

change how the datacenter is found
Merge pull request #67 from dcondomitti/proxy_support

Add proxy support for interacting with vSphere server.
version/changelog ++
Added support for datacenters in subfolders
Merge pull request #77 from andrewfraley/master

Added support for datacenters in subfolders