Mention ARCHIVE=1 in Makefile.OpenArena
Clear referenced paks when disconnecting

After playing Team Arena, if you switch to Q3A and try to play a demo with
cl_allowDownload enabled it would print "Need Paks: blah blah" and not play the demo.
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' into experimental/latest-libraries
Fix sending pk3 download error messages to clients

Disabled in e52a492f615e1245d6d22a84d2cc100c6d2f9f88.
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' into experimental/latest-libraries