wip/rthread 0.1.1 NetBSD

Python standard library contains thread library which provides primitives for writing multi-threaded programs. There are primitives for locks (allocating, acquiring and releasing), getting an identification of the thread, raising an exception in the main thread and, most importantly, start_new_thread function for starting a new thread.

rthread library introduced here mimics the interface of thread to some extent. The objective is to make distributed computing look and feel similar to multi-threaded programming