Jan 31, 2011: state of the thread system, report, from Bill Furnish

    I was unable to get exclusive mode working -- however synchronized IO
    mode does work correctly.  This guarantees that flushing a net is
    atomic.  It does not guarantee that flushing a net followed by a
    separate endline is atomic.  In particular this should fix the weird
    line corruption issues when printing in other threads on cygwin.
    Exclusive mode was going to be the lockout writing from other threads
    mode.  It "sort of" works.  It locks out input from all but the main
    thread, but unfortunately the input from the other threads is lost
    into the ether.  This could probably be fixed with a way to pick which
    thread should be the exclusive owner (low level C functionality
    exists) plus a significant amount of extra io code.  But the framework
    is in m2file.cpp and its commented well enough that other people can
    work on it.

    I've made a wiki tutorial on using the framework at
    http://wiki.macaulay2.com/Macaulay2/index.php?title=Parallelization so
    that people will be able to easily get up to speed on using the
    framework.
