Several improvements to pages, images and typography

Pages can now display their last modification date, using the dt-updated microformat for IndieWeb compatibility.
Images in notes are no longer deformed on smaller screens, thanks to improved responsive image attributes.
Blockquotes in articles are now styled with the monospace font which now correctly renders accented characters.
Font subsetting has also been improved: the script font is now instantiated to a single static variant before subsetting, reducing its size by 90%, and the monospace fonts now include the full French character set.
On the photos and jams pages, polaroids and sleeves now share consistent shadow and rotation effects, giving them a more tactile appearance.