Changelog

Aug 10, 2025: Initial course material.
              Improved Figure 21 in OpenPBR course notes (no version bump).
              Minor tweaks to OpenPBR slides (no version bump).
Aug 12, 2025: Slides for EON talk.
Aug 13, 2025: Minor fixes to OpenPBR course notes (v1.1).
              Updated speaker notes and additional slide (221) for PDI presentation (no version bump).
Oct 05, 2025: Minor aesthetic tweaks to Alain Hostettler's slides (no version bump).
              Updates to PDI slides (v1.1):
                  - Additional speaker notes about contrast sensitivity function on slide 52.
                  - Corrected typo in equation on slide 150.
Oct 28, 2025: Further updates to OpenPBR course notes (v1.2):
                  – Fixed more typos, broken links, and formatting issues.
                  – Added a derivation of the coat darkening effect for a specular base.
                  – Added brass and steel to the table of fits to measured metals.
Dec 23, 2025: Updates to Andrea Weidlich's course notes (v1.1):
                  - Added reference for "flexible layering systems" to section 2.1.
                  - Clarified performance timings in section 3.2.
                  - Added more detail regarding LODs to section 4.2.
                  - Minor rewording for clarity elsewhere.