Release 1.0.0b28

The user-visible changes in this release are:

• A new %include directive that parses a source file and pulls it in to the AST at the current point – this means it will be effectively indented into the same scope as the directive, including having access to any names defined at that point and evaluating into the current sequence.
• Support for flipping !images.
• uv_remap=:sphere now correctly inserts a seam at the 0° longitude line and wraps the texture mapping around. You will probably also want to be using repeat=true to get this to work correctly.
• !flare now supports halos around bright spots as well as starbursts and ghosts. No user-controllable knobs for this.
• Spotlights are now allowed to have up to 360° cones if you want (yes, I know that's not a cone).
• !model vertices=... no longer needs to have faces=... specified. If you don't give it then the engine will shrink-wrap the vertices with a convex hull.
• New << inline append operator – best understood from the docs.
• The old stable-state simplifying machinery has been replaced with let stable. This allows defining arbitrary names/expressions that are expected to be mostly static. The engine automagically manages (re)simplifying the code on these values. Again, more in the docs.
• !canvas should now work on Wayland.

Other that these changes, there's been a bunch of bug fixing – particularly in the use of the manifold3d engine for CSG operations.

Full Changelog: v1.0.0b27...v1.0.0b28