Haketilo

[UNTESTED- will test] Add filtering for http-equiv CSP headers

Remove unnecessary imports of url_item and add a CSP header-parsing function

The parsing function isn't used yet; however, it will eventually be as a less
destructive alternative to handling headers as indivisible units.

Merge rebranding to "Hachette"

Merge commit 'ecb787046271de708b94da70240713e725299d86'

Refer to the extension consistently as "Hachette" and remove TODOS.org
from the copyright file

Streamline and harden unique values/settings

The base URL is now included in the settings. The unique value no longer uses
it directly, as it is included by virtue of the settings; however, the number
of full hours since the epoch (UTC) is now incorporated.

Revamp signatures and break header caching on FF

Signatures, instead of consisting of the secure salt followed by the unique
value generated from the URL, are now the unique value generated from the
policy value (which will follow them) succeeded by the URL....

Use URL-based policy smuggling

Increase the power of URL-based smuggling by making it (effectively)
compulsory in all cases and adapting a structure. While the details still need to be worked out, the
potential for future expansion is there.

merge jahoti into master

Stop using the nonce consistently for a URL

Nonces are now randomly generated, either in the page (for non-HTTP(S) pages)
or by a background module which stores them by tab and frame IDs. In order to
support the increased variance in nonce-generating methods and allow them to...