1.4.1

Thread API change. Threads are now explicit structures instead of reference counted
resources. Thread notification changed to a signal beacon. Finalizing a thread will
join the thread and free resources.

Added beacon, a compound synchronization primitive unifying WaitForMultipleObjects
and epoll in a platform abstraction interface. Extended event streams to be able to
fire a beacon on event post.

path_directory_name now preserves protocols, path_subdirectory_name changed into
path_subpath which matches protocols and returns subpaths instead of subdirectories.