Fix docstrings in "colour.colorimetry.spectrum" module.
Updates references.
Fix reference access date in "colour.models.deprecated" module.
Update various references.
Add references scraping utility.
Update "Rec. 2020" colourspace transfer functions.
Update references for "Yoshi Ohno" in "colour.temperature.cct" module.
Update remaining references.
Merge branch 'feature/v0.3.1' into develop