The function set_point() sets the point POINT
to the value POSITION. Points may be specified by their labels which
the library defines as symbolic constants.
Legal position values are the symbolic constants STRAIGHT
and BRANCH for the respective point positions.
On successful completion the value SUCCESS is returned, otherwise the
value FAILURE.
int get_point(int POINT);
The function get_point() returns the position currently set
by the last call to the function set_point() for the specified
point POINT.
On successful completion either STRAIGHT or BRANCH is
returned, otherwise the value FAILURE.