Release new version

Features:
    - Highlight halfedge mesh elements that cause errors
    - Element IDs in halfedge editor UI
    - Scene import options
    - Warnings for halfedge configurations that cause export issues
    - Throughput term in rays
    - Instantly cancelling path tracer renders
    - Camera aperture and focal distance
    - Button to clear keyframe for all objects
    - Cone and torus object primitives
    - Save-before-closing-scene dialog given unsaved changes
    - Environment lights in rasterized renders
    - Keyframing for material properties
    - Keyframing for IK handles
    - Assignment 4 Task 4: simulating particle systems
        - Particle emitters as a new type of object
        - Keyframing for emitters
        - Custom particle meshes
        - Simulation system

Bug fixes:
    - consistent cmd+del keybinds on MacOS
    - force MSAA to a supported power of 2
    - undo for joint radius/extent
    - undo for keyframes, set/clear all, and crop
    - crash when deselecting...