Add Experimental Content-Security-Policy-Support (CSP) for Fauxton

Like every web application, Fauxton is vulnerable against XSS and
CSP is a technology that tries to help against that.

The patch makes it possible to enable CSP for the /_utils path and
allows configuration of the sent header.

The default setting for the value of the header breaks the old
Futon, when CSP is enabled there. The old Futon has alot of
inline-JavaScript which is not allowed in the setting I have
chosen as default.

For development, the header is also sent from the Node server
which launches Fauxton in dev-mode.

People can enable the feature by setting enable = true in the
section [csp] of their configs
Fauxton: Fix show me api link

 * use data-bypass attribute to circumvent backbone routing
Tentatively update version on master
Fauxton: Fix font awesome url to work for release
Fauxton: Content Security Policy optional for dev

This just makes the content security policy optional for
development.
add sinon.js
fix attachment view to bypass
Fauxton: Create fx roles

Fauxton auth works by checking what roles a user has and then decide if
they have access to a specific route. The only problem is a regular user
might get created but not have any roles. Unlike an admin user who get
assigned all the roles on creation.

The idea behind this is that certain routes should require a user to be
logged in but not necessary have any roles eg. #changePassword route.

This allows for a standard fauxton role that all logged in users get given so that
we can check via the roles if they are logged
Fauxton: Fix clone cancel button

This fixes the issue that when a user cancels a clone doc it goes back
to all docs. Now it just closes the modal.
add ZeroClipboard to LICENSE file
Fauxton: updated dev dependancies
Docs: fix typo in Accept header value

This closes #250

Signed-off-by: Alexander Shorin <kxepal@apache.org>