Handle return in parallel threads/processes.
Added test cases for return in threads/processes
Removed incorrect begin/rescue block from test cases
Revert version change (now again 0.6.3)
Use break to exit all threads
Version which should work: Threads can be broken, processes returned.
Fixed type in return message
Use Parallel::Break exception in both threads and processes.
Fix call to correct test case.
break -> nil
document break