SHA256 everywhere

Follow up #645. cc @mastahyeti 

* Move to SHA256 as default digest class
* Clarify byte digest vs hexdigest on Asset
* Cache raw byte digest and convert to hex or base64 when needed
Hmm. I'll have to read the spec again. I thought it suggested escaping, but
specifically called out / as not needing to be escaped.

On Wednesday, October 8, 2014, Joshua Peek <notifications@github.com> wrote:

> In lib/sprockets/utils.rb:
>
> >
> >        # Prepare/format the query section.
> > -      query = content_type ? "?ct=#{CGI.escape(content_type)}" : ""
>
> I'm pretty sure + will be fine since its query escaping requirement is
> mostly an http:// scheme browser relic.
>
> The ni rfc (http://tools.ietf.org/html/rfc6920#section-3.1) is kinda lame
> here and just delegates to the subsection of the URI query spec. Which will
> tell just you + is is a valid since the browser escaping quirk is not in
> any spec.
>
> It'd still be nice to ensure other reserved chars like & or = would be
> escaped. Though I don't think either of those are valid in the mime type
> grammar.
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/sstephenson/sprockets/pull/647/files#r18598266>.
>


-- 
-Ben Toews