linux-0.1.6-test5 fix for zombie sockets

test 5: I added MSG_DONTWAIT to the send and recv calls in case they forgot the socket is non-blocking. If that doesn't work, there's now the catch-all solution: another thread monitors the send/recv thread and terminates and restarts it if it stops. It prints "*** Restarting ThreadSocketHandler ***" in debug.log, and an error message displays on the status bar for a while. Before terminating, it tries closing the socket that's hung. If that works, it doesn't have to resort to terminating. I ran a test where it terminated the thread about 1000 times without trouble, so it should be safe. The terminate on linux is pthread_cancel, which throws it into C++'s exception handler. The thread calls we were using didn't have terminate, so I created our own wrappers in util.h to use CreateThread on windows and pthread_create on linux, instead of: _beginthread is windows only and lacks terminate boost::thread is really attractive, but lacks terminate wxThread requires you to create a class for every function you might call (yuck) File attached in the next e-mail