Attempt to fix objects getting multiplicated by objects getting deactivated in a different block than where they were loaded and then the original block, from where the static object was removed, not getting saved at unload

Add a log message to SEnv and make it load objects if there are < 51 of them, to load blocks that were limited to 50

Workaround for blocks having a huge amount of active objects; add log messages related to active objects for investigation

Better player damage prevention when falling on unloaded blocks, not involving getting stuck in there.

Switch more stuff to use the logging thing and fix segfault on player leave from server as introduced in a previous switch-to-logging commit

Use the logger; also, default to not showing much crap in console. Use --info-on-stderr to enable crap.

Make dungeon masters though and make oerkkis disappear when they get to you (because hitting them doesn't work for some unknown reason)

strict_protocol_version_checking setting; PROTOCOL_VERSION in clientserver.h; clean up defaultsettings.cpp and minetest.conf.example