node_tree 2.0.4

Node tree 2.0.4 fixes the look of the expanders and makes them themeable. No configuration or database change; update the code and clear caches.

- The boxed plus and minus expanders sat a little above the text: jqTree 1.9 lays a row out as a flex row and the module did not set the vertical alignment. The box is now centred on the title's line.
- The box, glyph and stroke sizes are CSS custom properties declared on ul.jqtree-tree (--node-tree-box, --node-tree-glyph, --node-tree-stroke), in em so they follow the tree's font size. A theme changes them by redeclaring the properties on the same selector, without editing the module; the README's Theming section shows this and the libraries-override route for replacing the module's CSS altogether.
- jqTree 1.9.1 (the current 1.x release) is the tested version: the Composer requirement, the CDN fallback and the status report's version check all point at it. Sites that install jqTree with Composer get it with composer update npm-asset/jqtree.