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

Fix single-frame lag in camera yaw/pitch, tune view bobbing and add wielded tool movement when walking and tweak stuff a bit