Header Field Parsing

[Oliver-Loeffler]

Implement a generic header field type and corresponding parser following the guide lines as defined in http://httpwg.org/specs/rfc7230.html#field.parsing .

• field name and value are separated with a colon
• no whitespace is allowed between the header field-name and colon, clients should not face this;
• consider removal of bad whitespace
• Remove preceding and trailing optional whitespace from field values
• consider field values following the "obs-fold" (obsolete fold) rule
• replace "obs-fold" by space (SP)
• consider other encodings than standard US-ASCII, treat other octets in field content (obs‑text) as opaque data