Firefox 68 sec fix breaks file access in local dir via xhr

[sharun-s]

Firefox has finally disabled local dir file access via xhr - https://www.mozilla.org/en-US/security/advisories/mfsa2019-21/#CVE-2019-11730

For history refer to comments in - https://bugzilla.mozilla.org/show_bug.cgi?id=1484620

This breaks...well everything :)

Unrecommended work around is to reset security.fileuri.strict_origin_policy. Should be fine in systems not connected to the net.

[Jaifroid]

Hey @sharun-s , I know you haven't committed to your Repo here since December, but just to say you've done some really amazing work here, and although this decision by Mozilla scuppers using your code from file:// , I've tested running your dev branch from localhost in Chromium (including Edge Chromium), Firefox and Edge Legacy (commenting out your "This only works in Firefox" code test), and your code to load a ZIM file without picking it is working beautifully.