Word types

There are 4 word types in Collapse OS. Whenever you have a
wordref, it's pointing to a byte with numbers 0 to 3. This
number is the word type and the word's behavior depends on it.

0: native. This words PFA contains native binary code and is
jumped to directly.

1: compiled. This word's PFA contains an atom list and its
execution is described in "EXECUTION MODEL" above.

2: cell. This word is usually followed by a 2-byte value in its
PFA. Upon execution, the address of the PFA is pushed to PS.
                                                        (cont.)