Added foundation for datapath manager.
Use datapath_id directly to retrieve dpn when creating a network.
Added DownloadInfo read-only object for accessing static information about the datapath.
Fixed use of datapath_info.
Moved the drop flows for broadcast mac addresses to DatapathManager.
Use items hash for tunnel manager.
Removed datapath from TunnelManager.
Added Tunnels::Base type and refactored TunnelManager.
Cleaned up logging and tunnel creation in TunnelManager.
Fixed specs for tunnel and network manager.
Refactored deletion of tunnels.
Fixed specs for tunnel manager refactoring.
Delete unused datapath networks from datapath manager.
Merge remote branch 'origin/master' into feature-datapath-manager

Conflicts:
	vnet/lib/vnet/openflow/switch.rb
	vnet/spec/vnet/openflow/network_manager_spec.rb
Fixed a lost change in the merge.
Fixed merge with master.
Fixed / worked around a deadlock in the creation of service interfaces.
Fixed method name when deleting a network.
Merge remote branch 'origin/master' into feature-datapath-manager

Conflicts:
	vnet/lib/vnet/openflow/interface_manager.rb
	vnet/lib/vnet/openflow/network_manager.rb
Fixed mac address variable in log statement.