[Round 3] Shoowa theme update

[Luya Tshimbalanga]

Reference:
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https://fedoraproject.org/wiki/Artwork/F9Themes/Shoowa


New update of theme with removal of lower dark colours. New diamonds
shape are added and fading effects is on the left part. Version 3.1c
uses gradient from the background in opposite direction. The sulfuric
diamond could be used for counting the number of week.
Comment is welcome.

Luya