Simple Inkscape Scripting v4.0.0

This is a major new release of Simple Inkscape Scripting. It includes two changes that break existing code but that provide improved functionality:

Change #1: width and height are no longer defined.
Replacement: Use canvas.width and canvas.height.
Reason: canvas.width and canvas.height not only are readable but also are writable, which is not achievable in Python with top-level variables.

Change #2: Group objects (as returned by group or layer) no longer define an add method.
Replacement: Use append for a single addition or extend for a list of additions.
Reason: Group objects now honor a rich set of standard list operations (append, extend, pop, len, etc.).

In addition to the above and the usual sorts of bug fixes, Simple Inkscape Scripting v4.0.0 provides a long list of new features:

• The image function can embed SVG files, not just PNG and JPEG files, as images.
• An objects_from_svg_file function merges SVG objects from another document into the current document.
• The ungroup method returns a list of objects that were released from the group.
• The clip_path and mask functions accept a list of objects in addition to a single object.
• Scripts can accept command-line arguments, provided via the user_args variable.
• The Simple Inkscape Scripting extension itself (an inkex.extensions.EffectExtension object) is accessible as extension.
• Path objects support translate_path, rotate_path, scale_path, and skew_path methods, which modify the path's control points themselves.
• An unremove method re-adds to the document an object that was removed with remove.
• The save_file function saves the current document to an SVG file.
• Two Simple Inkscape Scripting objects are considered equal if they share an underlying inkex object.
• The Simple Inkscape Scripting dialog box lets the user specify the input-file encoding (currently system-default, UTF-8, UTF-16, or Windows-1252).
• The font_family style attribute accepts not only a single string but also a list of strings. Hence, font_family='"New Century Schoolbook", "Times New Roman", serif' can be expressed more naturally as font_family=['New Century Schoolbook', 'Times New Roman', 'serif'].
• A new canvas object supports querying and modifying the canvas's viewport (physical size) and viewbox (coordinate system).
• Multi-page documents can be created in Inkscape 1.2+ using the page command.
• The all_pages function returns a list of all pages in the document.
• An inkex.colors.Color can be used directly in a style attribute (typically fill and stroke).
• The randcolor function returns a random color. Color channels optionally can be constrained to particular values.

See the Simple Inkscape Scripting commit log for details of all of the above.