Validate header names according to RFC 2616

Header name validation rules are too strict. RFC 2616 allows any ASCII character save from 0-32, 127, "(", ")", "<", ">", "@", ",", ";", ":", "\", <">, "/", "[", "]", "?", "=" and "{", "}".
update HTTP status codes to IETF RFC 7231

IANA Source: https://www.iana.org/assignments/http-status-codes
IETF RFC 7231: https://tools.ietf.org/html/rfc7231
Merge pull request #754 from tonyta/http-status-codes-update

Update HTTP Status Codes
Merge pull request #753 from vais/master

Avoid WEBrick handler buffering the entire response in RAM
Remove unused dependency from Deflater
Merge pull request #760 from igas/remove-require-from-deflater

Remove unused dependency from Deflater
Explicitly fail when hitting the multipart limit

Signed-off-by: Santiago Pastorino <santiago@wyeworks.com>
RACK_MULTIPART_LIMIT is a better name
MultipartLimitError => MultipartPartLimitError
allow overriding the rack multipart parser tempfile class

This allows for more flexibility in how to buffer (or stream) multipart
file uploads, rather than always using Tempfile and buffering to local
TMPDIR.
add rack.multipart options to lint and SPEC
Merge branch 'codekitchen-streaming-multipart'

Closes #639
Fix #639 wrong merge
Extract several methods from Rack::File#serving

Extracted methods:

  - mime_type
  - filesize
  - response_body

Closes #570

Signed-off-by: Santiago Pastorino <santiago@wyeworks.com>
Merge pull request #399 from EqualMedia/rfc2616-compat

Validate header names according to RFC 2616
Bump to 1.6.0.beta2
Rack::Lint and SPEC align with RFC7230 headers
Header specification change increments SPEC
Document the multipart_part_limit configuration in the README
Merge pull request #763 from byroot/multipart-limit-doc

Document the multipart_part_limit configuration in the README