Function load_from_jsin

tests/submap_load_test.cpp:766–780

static JsonIn submap_cosmetic( submap_cosmetic_ss );

static void load_from_jsin( submap &sm, JsonIn &jsin )
{
    // Ensure that the JSON is up to date for our savegame version
    REQUIRE( savegame_version == 33 );
    jsin.start_object();
    int version = 0;
    while( !jsin.end_object() ) {
        std::string name = jsin.get_member_name();
        if( name == "version" ) {
            version = jsin.get_int();
        } else {
            sm.load( jsin, name, version );
        }
    }
}

struct submap_checks {
    bool terrain = true;