Add gamut and tone mapping to glossary

Would be useful to describe exactly what these do and give some examples.

changed title from Add gumat and tone mapping to glossary to Add gamut and tone mapping to glossary

mentioned in commit a4ab4ed7

!58 (merged)

mentioned in commit 3c81a4d6

mentioned in commit 0821b9f8

mentioned in commit c7b040d2

mentioned in commit 21425114

mentioned in commit 32b1352b

mentioned in commit d73ccdf9

closed with merge request !58 (merged)