Switch the license to be LGPLv2/later, with small parts still remaining as GPLv2/later, by agreement of major contributors

Reimplement authentication handler in Lua; now we have 1) infinite privilege names, 2) minetest.register_authentication_handler()

Don't set m_removed on dead players (dead players are indicated by hp == 0). Local
damage flash is shown whatever the cause was (even from Lua set_hp). PlayerCAO
damage flash matches duration of local damage flash. Fall damage is dealt much more consistently (this is done by disallowing jumping when speed.Y is very negative, up to now jumping could sometimes negate fall damage)

Inventory menu (with dragging) improved. Crafting is now handled via a IACTION_CRAFT inventory action.

The huge item definition and item namespace unification patch (itemdef), see http://c55.me/minetest/wiki/doku.php?id=changes:itemdef

Remove stuff made obsolete by making players more ActiveObject-like and raise protocol version number by one (because it is not compatible at all anymore)

Fix processing of the default_password setting. It is now actually used as the plaintext password for new users. Also add /setpassword and /clearpassword server commands that can be used by admins with the PRIV_PASSWORD privilege, and update the /help message.