x--tile.jpg fixes

A script silly keeping the original extension even though tiles are low quality jpegs; A few PNGs that PIL doesn't like re-saved as PNG24; a run of the script to generate correct tile images
TBZPagePathToAssetPath srcset @2x bugfix
UX: Yearly archive as tiled index pages rather than paginating the diary index.

was too confusing having both, now URL manipulation and on-screen
navigation is clear and simple.
Removed Diary's RHS tab

…better not have it than have the half-finished functionality it
contained.
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