Only set content type for known types

A sender that generates a message containing a payload body SHOULD generate a Content-Type header field in that message unless the intended media type of the enclosed representation is unknown to the sender. If a Content-Type header field is not present, the recipient MAY either assume a media type of "application/octet-stream" ([RFC2046], Section 4.5.1) or examine the data to determine its type.

http://tools.ietf.org/html/rfc7231#section-3.1.1.5
Add Asset#charset
Rename input[:logical_path] to input[:name]
Basic gzip encoding server support
Add coding utils
Support server deflate
Ensure encoded body is still an Array
Register content encodings
Basic find_asset with accept_encoding
Find gzipped asset from manifest
Stop gzipping manifest by default
Don't define identity encoding
Pass options instead of bundle and accept encoding
Rename encodings
Dup paths on write
Copy mime type changes on write
Copy engines on write
Extract configuration module
Extend all off configuration
Centralize configuration copying