Add some nice aliases for /matchinfo (/info, /mi, /minfo)
Don't void kill when sleeping in bed above y=127. Thanks @Mojang

Addresses https://mojang.atlassian.net/browse/MC-3599
Inform players about update to preview mode (does preview mode work?)
Don't toggle nightvis and streamer mode. Explicit set and unset with -x
Update client timers during the match clock task