release: 1.3.73

release: 1.3.73

======

* 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