* Added the possibility to provide ImageIO's output format in the TYPE string.
For instance:
TYPE=png image/png
TYPE=png image/png png256
TYPE=png image/png png24
TYPE=png image/png png
* Removed useless comments.
Added documentation for output format.
* Added tests for 'webp' output format
* Also added tests for 'png32' output format
* Fix 'webp' sums vary based on version
* Add JPG & use multiple layers on example-map
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Co-authored-by: Tim <autintim@gmail.com>