Imported Upstream version 0.4.7
Merge tag 'upstream/0.4.7'

Upstream version 0.4.7
new upstream release
refresh our patches
build-depend on luajit
upstream dropped the 'common', 'build' and 'survival' mods for 0.4.7
Imported Upstream version 0.4.7+repack
Merge tag 'upstream/0.4.7+repack'

Upstream version 0.4.7+repack
we still need to repack to integrate the missing mods into the archive

even if upstream dropped most of the separate packages
upstream forced to use internal json, which is something we don't want to see happening

Also, search for json where it's installed on debian systems
bump standard version to 3.9.4 (no change needed)
update upstream changelog
get ready to release