* use the activate/deactivate system from WpObject,
  which allows async activation and error reporting
* drop 'module' property, use 'core' from WpObject

This one offers API to interract on a lower level with
the D-Bus reservation API and uses GDBus high level bindings only.

Also, this one implements the full Acquire procedure, calling
RequestRelease() on the peer and requesting the name again with
REPLACE_EXISTING