FIxed floating isle generation at chunk boundaries

A mapgen fix authored by paramat, as mentioned here: https://github.com/minetest/minetest/issues/989
Fix spaces float islands code
Fix "TODO read modinfo" in modmanager to improve ui usability
Fix win32/msvc i18n (quite UGLY version, blame Microsoft)
Disable localization workaround in server
Fix invalid usage of temporary object in mainmenu json conversion
Merge remote-tracking branch 'upstream/master' into die