Should make it easier to add/remove parameters without changing all calls to the
functions throughout the code.
Also adds an interface through which to call make_mp4_header().
- Calculate size for both formats (+ move the return to transcode_encode_query)
- Let transcode_needed() decide what format to output
- Determine content-type from transcoding type
- Add transcode-dependent ability to override file metadata in rsp/daap
- Send file size matching format
This change allows to reuse curl handles for multiple requests.
Reusing a curl handle improves performance if more than one request is
made against a service (connection, session cache, dns cache are kept
between requests).
