Merge pull request #106 from tomhughes/master

Allow the paths for introduction.{jpg,mp4} to be overridden
Default to OpenStreetMap site name
Merge branch 'master' of github.com:systemed/potlatch2
Localisation updates from http://translatewiki.net.
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Localisation updates from http://translatewiki.net.
Localisation updates from http://translatewiki.net.
Don't be befuddled by non-existent tiles
Localisation updates from http://translatewiki.net.
Localisation updates from http://translatewiki.net.
Localisation updates from http://translatewiki.net.
Localisation updates from http://translatewiki.net.
Localisation updates from http://translatewiki.net.
Notice no longer needed
Localisation updates from https://translatewiki.net.
Localisation updates from https://translatewiki.net.
Localisation updates from https://translatewiki.net.
Localisation updates from https://translatewiki.net.
Localisation updates from https://translatewiki.net.
Localisation updates from https://translatewiki.net.