Fix #138 & #139

Fix #138 & #139

- use chord formatting for single tie

- add all notes + accidentals to chord outline

- separate file for Tie_specification

- use convex_amplifier for distance penalties:
penalties increase superlinearly in distance

- tunable padding for skyline

- semi tie: set direction with ^ and _

- debug output for semities

- for single tie case, introduce penalty for wrong direction

- only add symmetry penalties for more than 1 tie.

- use exactness to determine whether to override delta_y_ too.