Refactor for stream->_av.

- move _av into stream critical section.  ( HCC accelerator_view is not
  thread-safe but HIP steram is. )
- Refactored many places in code that need to acquire critical section.
some were previously thread races, ie enqueueing marker.

-remove support for GRID_LAUNCH_VERSION < 20
-Enable USE_AV_COPY based on HCC work-week.
- Review hipModule docs, some calrity/editing.

Change-Id: I3ce7c25ece048c3504f55ecd4683e506bb1fc8b6

src/hip_stream.cpp

@@ -84,6 +84,10 @@ hipError_t hipStreamWaitEvent(hipStream_t stream, hipEvent_t event, unsigned int
 
     hipError_t e = hipSuccess;
 
+#ifdef USE_AV_COPY
+     printf ("USE_AV_COPY\n");
+#endif
+
     {
         // TODO-hcc Convert to use create_blocking_marker(...) functionality.
         // Currently we have a super-conservative version of this - block on host, and drain the queue.