(last_known_column): Now a float.

(last_known_column): Now a float.
(current_column_1, position_indentation, current_column,
string_display_width): Return float.
(Fcurrent_column): Cast `current_column' return value to int.
(Fcurrent_indentation): Cast `position_indentation' retval to int.
(indented_beyond_p): Third arg now a float.
(compute_motion, vmotion): Cast `indented_beyond_p' 3rd arg to float.