- Add pointer member to thread. This is the current executing block.
- Add stackFrame member to thread. This is the current frame
information like procedure parameters.
This is a step potentially towards stack-less threads. With further
modifications we could have stack and stackFrames be null if a script
does not call a procedure.
Threads are now removed after every "inner" step. Any thread that
reaches its DONE conditions is immediately removed instead of requiring
an extra step to remove it. As such tests that check the number of
threads have been updated to consider this.
Store the thread's blocks at blockContainer letting execute quickly
determine the block source. Monitor threads are a monitor thread. They
do not become a target thread suddenly.
