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

minetestmapper: Fix the way ylist is computed, use cStringIO instead of rolling own Bytestream, remove some artifacts when drawing underground blocks, introduce a --drawunderground switch (defaults to of), 'blocknum' renamed to 'content'.

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

Fixed null pointer dereference errors found by cppcheck

Put the random interval back to 1 in 50 chance. It's not as rare as rats, but rarer than grass.

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

Simplistic wielded tool lighting, added setMeshVerticesColor to utility.h and refactored some other code into calls of that

Create a separate scene manager for the wielded tool. This fixes the glitchyness in large map coordinates and some depth buffer problems. (The tool doesn't bob anymore when walking, this will be fixed later.) Fix MSVC build (thanks to dannydark).