Remove unnecessary smooth_crash decorator, will now be used only for top level call of a thread.

The RootTask has a more complex try except to handle post execution cleaning.
Exception in task will set the should_stop flag, if no task in the other threads check for it the program will not stop. Users should not disable stopping capabilities too lightly.
Add two facilities tasks to break or continue a loop.

For now hard-coded to work only with LoopTask (should be extended to WhileTask when written).