CSP header image-src should be img-src

[kmturley]

In this example of your documentation image-src should actually be img-src:

csp = {
    'default-src': '\'self\'',
    'image-src': '*',
    'media-src': [
        'media1.com',
        'media2.com',
    ],
    'script-src': 'userscripts.example.com'
}

Also would be useful to show the way to pass in the settings e.g:

csp = {
    'default-src': '\'self\'',
    'img-src': '*',
    'media-src': [
        'media1.com',
        'media2.com',
    ],
    'script-src': 'userscripts.example.com'
}
talisman = Talisman(app, content_security_policy=csp)

I had to search the source to find how to pass it through :)

[theacodes]

@kmturley would you be willing to submit a PR to fix that? :)