Always generate consistent gzip
Change WOFF MIME type to `application/font-woff`

The WOFF MIME Type was formally registered as `application/font-woff`:
- http://www.iana.org/assignments/media-types/application/font-woff
Merge pull request #591 from alrra/woff-mime-type

Change WOFF MIME type to `application/font-woff`
Include all cache related headers on 304
Default erb content type to text/plain
Fewer magic test numbers
@digest is no longer used
Don't need to "expire cache"
Make logger global configuration
Move context class to global config
Make digest_class global config
Make version global
Copy over root in configuration
Tidy whitespace
Skip context require
Ensure accept encoding content type is set
Assert content encoded etag is different than unecoded etag

Note: Content codings are a property of the representation data, so a strong
entity-tag for a content-encoded representation has to be distinct from the
entity tag of an unencoded representation to prevent potential conflicts
during cache updates and range requests. In contrast, transfer codings apply
only during message transfer and do not result in distinct entity-tags.
Speed up Manifest#clean by reducing complexity

Change cleaning old compiled assets from using a O(n^2) to a O(n)
algorithm for finding old files to remove. This matters since there
can be thousands of assets.
Merge pull request #597 from jeltz/faster_clean_assets

Speed up Manifest#clean by reducing complexity
Make silence_warnings a global method