Merge pull request
#2791 from minrk/forksafe_nomp...
Merge pull request
#2791 from minrk/forksafe_nomp
forward stdout from forked processes
uses zmq instead of multiprocessing, because mp has too many issues.
- messages are sent via PUSH/PULL from subprocesses
- messages are sent at flush time, not at write time
- subprocess messages
- no threads, no sync events, etc.
some basic tests are included
closes
#2438
