Setting for game starttime in local timezone

Provide a setting to display the game starttimes in local timezone.
Needed to import the calendar module since working with timestamps and
timezones is a bit tricky in python.
settings button in main menu

Closes Issue #77.
Tweak settings text
Bugfix - resetting items

There sneaked a bug in, when first selecting Game Pass and weeks and
then Network - Network Live. After stopping the playback, the earlier
selected games were shown.