No longer hide players who are dead. With models, a death animation should be used instead

Some changes requested by celeron55

Rename a lot of things in the code, and use better lua api function names

Minor code corrections

Bump protocol version up, since the models / animations / attachments code creates new client<->server messages

Update attachments at the ending of the addToScene function for parents. And with this... *drum roll* Client-side attachments are at last functional and stick visibly.

Fix the last segmentation fault (apparently). So far attachments seem to be fully functional, although removing the parent causes children to go to origin 0,0,0 and possibly still cause such a fault (though this should already be addressed)

Fix a bug in falling code where entities get stuck

Also check if the parent has been removed server-side, and detach the child if so. Fixes children going to origin 0,0,0 when their parent is removed.

Unset all attachment properties when permanently detaching (on both the client and server). Also store less data we don't need

Create a separate function for detaching, and also update lua api documentation

When a child is detached, update its position from the server to clients. This WILL cause it to get positioned slightly differently client side, as the server attachment system only copies parent origin and knows not about mesh / bone transformation. This prevents different clients seeing the object detached in different spots which is most correct

Update the position of attached players to clients. An attached player will see himself move, but this is currently VERY ugly and laggy as it is done by the server (it probably must stay this way too)

Use a different approach for locally attached players. This allows for smooth positio transitions to work, as well at the player turning around freely. Still buggy however

- You have 2 stacks: a with x items and b with y<x items
- Take a with your mouse and place it on b
- Whole stack a moves to b
- (y * 2 - x) items move from b to a
- (x - y) items are left to the mouse cursor

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

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

Inventory menu changes: Tooltips; dragging; drop from menu. Lag is a bit annoying (even in single player).

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

Also contains some commented-out code for testing out different looks
in the future.

This allows us to map the keys which are not considered in
irrlicht's EKEY_CODE system, such as \, [, /, ] etc.