break keyword to interrupt loops

## Description

Inside a `for` or `while` loop, the command `break` forces the end of the loop.

## Examples

    k=0;
    while 1==1,
    	  k=k+1;
    	  if k > 100 then
    	     break
    	  end;
    end

## See also

- while
- if
- for
- abort
- return

## History

6.0.0 `break` is now protected: Assignments like `break=1` are no longer possible.