Changes:
- Added Layouter trait for Weave graph layout implementations
- Added built-in Layouter & Bézier curve fitting implementations behind new default
layoutfeature - Added DependentWeave::new() and IndependentWeave::new()
- Replaced DependentWeave and IndependentWeave shrink_to() with shrink_to_fit()
- Tweaked DependentWeave and IndependentWeave Default implementations
- Removed legacy DependentWeave implementation while retaining support for legacy DependentWeave format
- Minor IndependentWeave optimizations
- Tweaked Node, Weave, and ImmutableWeave trait definitions (breaking change for third-party trait implementers)
- Added DiscreteContents and IndependentContents implementations for
()type - Minor improvements to DependentWeave and IndependentWeave documentation
- Substantial code cleanup
- Updated dependencies
- Updated README feature list