merge pull request #75 - proper shutdown (ctrl-c or process kill) [for terminal-less operation]

shutdown detection re-done:
- remove wait in raw_input()
- add signal handler "shutdown" to PlexConnect
- disable CTRL-C in WebServer, DNSServer
Attention: now controlled shutdown is CTRL-C instead of ENTER.
Added a clock to the video player :) Can be turned on/off in settings.