Fine-grained locking for events

[Sebastian Huber]

This patch set adds basic support for fine-grained locking on a per-object
scope.  The Giant lock is only used for the blocking operations (thread state,
scheduler, watchdog).  It uses the RTEMS events do demonstrate the basic
functionality.  The basic idea is to store the intermediate thread blocking
states in the thread control block and not in global variables or thread
queues.