fixed shutdown of plugin

made stop() synchronously and made the destructor virtual
added private copy ctors to prevent copying of plugin objects
changed close() method to take an l-value which is reset by it
fixed shutdown of plugin

epoll_wait() does not return when the epoll-fd is closed by another thread.
Use a helper pipe which is added to the epoll.  Closing one end allows to
terminate the thread cleanly
fixed minor typo
destroy the controller object within Stop()

due to lot of static objects in vdr, implicit destruction of objects has unpredictable
effects :(
fixed magic key behaviour
fixup! added private copy ctors to prevent copying of plugin objects
udevhelper: fixed minor warning
make: added some default -W options
refactored epoll event handling
fixup! refactored epoll event handling
solved list removal in a better way
initialize dev_t_
made valgrind happy by passing valid memory to EVIOCGRAB
fixup! fixed shutdown of plugin