* encode: implement prefer setting
* encode: minimum_length configurable via caddyfile
* encode: configurable content-types which to encode
* file_server: support precompressed files
* encode: use ReponseMatcher for conditional encoding of content
* linting error & documentation of encode.PrecompressedOrder
* encode: allow just one response matcher
also change the namespace of the encoders back, I accidently changed to precompressed >.>
default matchers include a * to match to any charset, that may be appended
* rounding of the PR
* added integration tests for new caddyfile directives
* improved various doc strings (punctuation and typos)
* added json tag for file_server precompress order and encode matcher
* file_server: add vary header, remove accept-ranges when serving precompressed files
* encode: move Suffix implementation to precompressed modules
