Svgling

This version is intended to be the last release that is marked as
a beta / pre-1.0 version.

New features:

- Support for arbitrary SVG node contents, via the `node_builder`
decorator
- Support for handling of custom tree node classes, via the `TreeOptions`
option `tree_split`, as well as a pre-provided handler for nltk's
`ProbabilisticTree` class
- Built-in node builder (`svgling.core.subscript_node`) for nodes that
have a subscript
- A figure class `HTMLSideBySide` that allows mixing hybrid HTML diagrams
with SVG diagrams

Documentation:

- Major documentation improvements, convert docs to quarto

Fixes, improvements, changes:

- Support a repeated call notation for most TreeLayout public functions
- Improvements to the `draw_tree` and `tree2svg` APIs
- Fix for constituent underlines at the exact lower edge of a figure
- Compatibility mode for rendering (some) `svgling.html` diagrams in quarto
- Refactor of the node construction API that goes along with the `node_builder`
change
- Build/install improvements

As of 0.3.1, `svgling` is the default tree-drawing package for `nltk` Trees
in Jupyter; this update provides better compatibility for that. It also
improves some styling options, and direct support for format conversion.

New features:

- Limited per-node styling in trees: supports changing font style, size, and
color/fill
- convenience wrappers to make conversion to PNG/PDF via the `cairosvg`
package easier (`cairosvg` is now an optional package dependency)
- Support `nltk.Tree` objects directly in `svgling.figure` classes

Fixes, improvements, changes:

- Simplify import code for nltk, remove monkeypatching
- The option `global_font_style` is renamed to just `font_style`
- Refactor `TreeOptions` to make it easier to pass around options bundles
- Default change: `relative_units=False`. This provides better compatibility
with inkscape, among other things. This option is now deprecated.
- Documentation improvements

New feature:

- Compatibility mode aimed at Inkscape: allow using `px` instead of relative
`em` units. This allows current versions of Inkscape to load the output
SVGs. This mode is not on by default.

Fixes, improvements, changes:

- Update documentation to reflect some issues in MathJax math mode delimeter
choice for hybrid mode.

New features:

- Basic support for drawing trees using a mix of HTML/CSS (for positioning) and
SVG (for line drawing). This is much more limited than the core drawing
algorithms, but allows for arbitrary node labels + MathJax.

Fixes, improvements, changes:

- Improve documentation

New features:

- Support for multi-line nodes.
- Edge styles, muti-segment descents for level skipping.
- Wrote a manual.
- Tree annotations: movement arrows, constituent highlighting / underlining.
- Complex figures: grids of trees, captioning.

Fixes, improvements, changes:

- Massively improve responsivity of svgling diagrams.
- TreeLayout objects manage font size directly.
- `distance_to_daughter` is now a distance between levels, i.e. excluding node
height.

- Fix for non-leaf nodes that are larger than the leaf nodes they dominate.
- More flexible arguments to `draw_tree` (will accept the top node + children
via variable arguments, rather than a list/tuple as the first argument.)
- Documentation improvements.