Clean up 'stats' methods, which were not based on machine values.
Additional work required here to get network stats correct and
to update storage pool used stats.
Clear up Stats tests.  They are not on by default at this point,
but have been tried.
Dead code from previous attempt to provide support for Hyper-V.
The hypervisor control engine expects a server resource agent object
corresponding to a connected agent (an agent not in the managment server
e.g. executing on remote hardware).  We use the HypervDummyResourceBase
for this.
Move server-side portions of Hyperv Plugin to the plugin's folder.
Makes merging to master easier, because all files sit independent
of the management server's source.