partial: 1.3.73.jcn

partial: 1.3.73.jcn

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* Robustness fix for minimise_least_squares ()

* cleanups of Slur_bezier_bow, removed Bezier_bow.

* cleanup of Tie. Changed Tie into interface. Made ties flatter by default.

* changed SCM_UNDEFINED to SCM_UNSPECIFIED for return values that go
back into Scheme.

* changed SCM_UNSPECIFIED to SCM_EOL for undefined element
properties. This makes initializing list properties redundant.

* removed idiotic code for including tfm.[1-5] into search path.

* fixed problem with tuplet placement for cross staff tuplets.

1.3