For some unknown reason, all the `document.onreadystatechange = () => {`
checks stopped working. Thankfully, replacing them with
`document.addEventListener("readystatechange", () => {` fixed the
issues.
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Signed-off-by: George Araujo <george.gcac@gmail.com>
Fixes#2419 by downloading leaflet images. Also changed the path where
the libraries are downloaded to avoid not downloading files with same
name.
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Signed-off-by: George Araujo <george.gcac@gmail.com>