* Efuns
* Lfuns
* Shadow

There are two kinds of predefined functions:

efun
The functions hard coded, which are defined by the game driver. They can be 
redefined by a local function of the same name, which will then be used 
instead.

lfun
Functions that optionally can be defined by the objects. These functions will 
be called by other lfuns, and sometimes by the game driver. They will control 
how the object will behave in special situations. An example is get(), which 
if defined and returning 1, will enable the object to be picked up by players.
If returning 0, then the player will get a message that says that the object 
can't be picked up.