Reorganize core service package, fix several issues
Switch core resource handlers to synchronized registration
Refactor debug API, debug plugin activation, fix several issues
Move some classes in core, fix some bugs
Add forwarding providers and managers
Reorganize debug classes, improve debug loading
Update manifest files
Implement first preferences plugin draft
Add exception messages to enum constant supports
Switch command handlers back to asynchronous registration
Unsupport command change handler for now
Fix minor debug output issues, fix some null pointer exceptions
Update preference store keys