* lily/tie-formatting-problem.cc (find_optimal_tie_configuration):

* lily/tie-formatting-problem.cc (find_optimal_tie_configuration):
new function. Search region of 3 positions for best tie.
(score_configuration): new function.
(score_aptitude): new function.
(generate_configuration): new function.
(get_configuration): new function.
(Tie_formatting_problem): new function

* input/regression/page-top-space.ly: a6 for page-top-space demo.

* lily/include/tie-formatting-problem.hh (class
Tie_formatting_problem): add Tie_details to
Tie_formatting_problem. Update calling conventions.