Enable the delete button that's been hidden away so far. When clicked, we
suffix the cached json file with '.deleted'. This also causes a popup with an
undo button to appear (taken from Nautilus). When clicked, that button will
restore the drawing again.
This is really all just renaming anyway, because nothing ever gets deleted
here.
An extra filter is needed to skip Tuhi drawings that have been deleted in the
GUI - we don't want to add the drawings we just deleted again just because
Tuhi still keeps them in cache.
Tuhi caches the json data but has no guarantee about storage. So we cache the
json we get from Tuhi and store it in our settings dir through our Config
backend. Then we use those cached values to generate the SVG files.
This is saved for posterity in the new settings file, so we need a new Config
object (singleton is enough here).
For now, whenever the orientation changes, we just wipe our UI and re-generate
all SVG files. Much easier than messing with proper SVG rotation given that a
device should only ever change between rotations once.
Peter Hutterer