xml: fix to use only xml_location_t typedef
fsm-policy: Add ni_fsm_policy_location()
fsm: Correct <client-info> and <client-state> handling

To be properly handled within nanny and client's FSM.
To prevent nanny crash on updating <client-state>
xml: Add xml_document_is_empty() function
client: ifdown deletes the Factory created devices
server: Drop interface's state file on RTM_DELLINK
client_state: Use index instead of name in state-*.xml files
fsm: Add tranistion from DEVICE-UP to DEVICE-EXISTS

This transition should call shutdownDevice() method.
cleanup: remove variable names from prototype declarations
bonding: Add shutdownDevice() method handler

Release all bonding slaves on shutdownDevice().
bridge: Add shutdownDevice() handler for bridge interfaces

On shutdownDevice() call, the bridge's port are getting deleted
and removed from the port's list.
Merge pull request #123 from pwieczorkiewicz/merge-04122013