Reshuffle functions to define them in reverse
calling order (C style).
This allow us to define templates before they are
used. Currently it is not like this, for instance
evaluate_pieces is defined after do_evaluate that
calls it. This happens to work for some strange
reason (two phase lookup?) but we want to avoid
code that works 'by magic'.
As a nice side-effect we can now remove the function
prototypes.