1. device export proxies must be destroyed manually since they are
not associated with the WpRegistry
2. the monitors should not disconnect before all WpSpaDevice objects
are destroyed; remove the manual disconnect call and let GObject
ref counting do its job (the core will disconnect when its last ref
count is dropped after the last monitor plugin is destroyed)
+ rename FEATURE_CONTROLS to FEATURE_PROPS
+ add accessor for the standard spa_param_info (info->params)
+ hide the low-level params API that nobody uses
* core no longer exposes create_remote/local_object
* node, device & link have constructor methods
to enable the create_remote_object functionality
* added WpImplNode to wrap pw_impl_node and allow creating
"local" node instances
* added WpSpaDevice to wrap spa_device and allow creating
"local" device instances
* exporting objects in all cases now happens by requesting
FEATURE_BOUND from the proxy, eliminating the need for WpExported
* replaced WpMonitor by new, simpler code directly in module-monitor
* the proxy type lookup table in WpProxy is gone, we now
use a field on the class structure of every WpProxy subclass
and iterate through all the class structures instead; this is
more flexible and extensible
