Make Connection::Receive return the data via a SharedBuffer reference, so the caller doesn't have to choose the right buffer size in advance.

Conflicts:

	src/test.cpp

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.

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

Adding (most) of the sapling functionality. It has yet to work, since MEET_OTHER was not implemented at the time of this commit. Hopefully it will work when merged with celeron's latest.

Make client report a newer version number to the server than 2011-07-31 does and make the server enforce it