At least on Retina Macbook Pros but most likely on other configurations,
the viewport's sizes is not exactly consistent to integer.
For instance, on a maximized Firefox, document.body.offsetHeight is 1,600.
When looking at the <html> on the inspector, I'd get 1,599.6, so **roughly** the same
but not exactly. Those inconsistencies are present on every level so being too strict
about those is probably not adequate.
This fixes#603 but allowing a 2% margin on the scroll position
to match the _end of screen_ and thus trigger the loading of additional cards.
This means that for the example above, it triggers at 1,568 instead of never reaching 1,600.
2% might be too large but it seems safe considering the potential of various resolutions
we may encounter and I don't see any side effect.
Before this fix the /random endpoint could return a 404 Not Found page
saying
The requested URL "/random" was not found on this server.
Error cases producing such a result were:
- `/random?content=NON-EXISTING-BOOK` (can happen when a server is
restarted or the library is reloaded and the current book is no longer
available).
- Failure of the libkiwix routine for picking a random article.
Now a proper message is shown for each of those cases.
Deduplicated the mustache templates static/templates/catalog_v2_entries.xml
and static/templates/catalog_v2_complete_entry.xml (the latter was
renamed to static/templates/catalog_v2_entry.xml).
