Reduce the height of tree UV coordinates to work around mipmap issues.
Allow adding a contition to locked-track animation
Prevent timer endless loops
Add (optional) uv coordinates to SGPickCallback
Extend SGPickCallback to allow passing more information to callbacks
Use simulation time for spin and timed animations
Avoid UV bleeding issues on trees by using a strip of textures.
Canvas: proper forwarding of dirty and visible flags within nested canvases.
Canvas: Add local_pos to mouse event and fix transformation of event positions with multi-level nested canvases.
Use square textures for trees, with shrunk UV coordinates.
Canvas: bug fixing and add some helpers.
Canvas: separate CSSBorder parsing from image.
Canvas: add chainable helpers to Path for adding segments.
Canvas Image: fix updating while showing nested canvas.
Support for parsing basic CSS color keywords.
Move BlendFunc parsing to separate file for easier reuse.
More helper methods for Canvas and PropertyBasedElement.
Make nasal::Ghost usable with weak_ptr
Canvas: set blend function for elements and prevent autoresize
Canvas: clear event listeners on destroy

Removing all event listeneres on destroying a canvas
prevents circular references due to Nasal event listeners
keeping a reference to the canvas in their closure.

Also fix event handling with direct children of the root
group and add some more helpers to the Canvas.