* ./modules/misc/testsuite/test4.c: added a stress test module; doesn't get

    compiled yet because it uses the "command" variables I'm about to check
    in. They need to be typed in the rc interface for instance (-I rc). This
    module has two available commands: "signal <int>" which sends the given
    signal to the vlc process, and "stress [<int>]" which performs a series of
    object creation/lookup/destruction, variable creation/setting/destruction
    and thread spawning/joining tests. The optional argument for stress is an
    integer between 1 and 200 (the bigger, the heavier the tests; it may hang
    your machine at around 150, be careful).