Removed antipattern abstraction RsSingleJobThread
Rename runloop() method to run() in RsThread
Ported few classes ineriting from RsSingleJobThread to RsThread
RsThread use std::atomic instead of self implemented strange binary semaphores
Removed RsTickingThread::shutdown() use RsThread::askForStop() instead
Removed RsTickingThread::fullstop() use RsThread::fullstop() instead
Stop properly JSON API server in retroshare-gui
Centralize errno traslation to literal in util/rserrno.*