- Use a hardcoded default value of 10 files per page.
- Save cover sizetag as "s<nb of items per page>" instead
of "s<item height>" so they are stable (and not re-fetched)
when switching between FileBrowser and History, which have
some small geometry differences.
- When showing History in landscape mode, decrease perpage
from the set value, so items don't look smaller.
- Use a step, larger with big items, when iterating and decreasing
font sizes to make text fit, to speed up the process a bit.