Fix test failure from ResourceManager.
Merge SettingsArgs into SettingsMap.
Fix mMap==null in new SettingsMap ctor.
Fix KeyListeners not being notified.

Because toString() was being used and getKeyName()'s were being bound.
Nothing was working by key-specific binding;).
Settings implementation notifications now work, and use new API.
PcDisplayManager + ResourceManager now uses subscriptions.

This also means that with this commit the NotificationManager
interface is suitably fleshed out for use ;). It took a bunch of
commits to get things ironed out in available time.
Change Settings.OnChangedListener.onChanged() prototype.
Logging is now a Subsystem.
Whitespace issue in ResourceManager.
debug=true Setting now sets log level Log.DEBUG.
log_type is now log_to.

This is more correct now that it has taken on the log_file property.
Previously it was log_type=file and log_file=filename. Now it's any
non special (stdout, stderr) log_to is taken as a filename.