Merge branch 'Mario/q3compat_sanity' into 'master'

Merge branch Mario/q3compat_sanity (M merge request)

Closes #2281

See merge request xonotic/xonotic-data.pk3dir!856

diff --cc qcsrc/client/mapvoting.qc
Simple merge

diff --cc qcsrc/common/mapinfo.qc
Simple merge

diff --cc qcsrc/common/mapinfo.qh
Simple merge

diff --cc qcsrc/server/mapvoting.qc
Simple merge

diff --cc qcsrc/server/world.qc
Simple merge

diff --cc qcsrc/server/world.qh
Simple merge

diff --cc xonotic-server.cfg
Simple merge