On Linux, using Python (and in particular the Tk Python console) could cause an infinite
pthread_join wait while exiting the application if it had been detached from the calling terminal.
This happened during processing of 3rd-party (BLAS) atexit code. As a workaround, a 15s timeout
has been implemented that raises SIGTERM to exit the hard way.
Merge branch 'master' of https://github.com/RJVB/xgraph
post Linux mod merger