[config] opts for http header parsing strictness (fixes #551, fixes #1086, fixes...

[config] opts for http header parsing strictness (fixes #551, fixes #1086, fixes #1184, fixes #2143, #2258, #2281, fixes #946, fixes #1330, fixes #602, #1016)

server.http-parseopt-header-strict  = "enable"
server.http-parseopt-host-strict    = "enable"  (implies host-normalize)
server.http-parseopt-host-normalize = "disable"

defaults retain current behavior, which is strict header parsing
and strict host parsing, with enhancement to normalize IPv4 address
and port number strings.

For lighttpd tests, these need to be enabled (and are by default)
For marginally faster HTTP header parsing for benchmarks, disable these.

To allow
  - underscores in hostname
  - hypen ('-') at beginning of hostname
  - all-numeric TLDs
  server.http-parseopt-host-strict    = "disable"

x-ref:
  "lighttpd doesn't allow underscores in host names"
  https://redmine.lighttpd.net/issues/551
  "hyphen in hostname"
  https://redmine.lighttpd.net/issues/1086
  "a numeric tld"
  https://redmine.lighttpd.net/issues/1184
  "Numeric tld's"
  https://redmine.lighttpd.net/issues/2143
  "Bad Request"
  https://redmine.lighttpd.net/issues/2258
  "400 Bad Request when using Numeric TLDs"
  https://redmine.lighttpd.net/issues/2281

To allow a variety of numerical formats to be converted to IP addresses
  server.http-parseopt-host-strict    = "disable"
  server.http-parseopt-host-normalize = "enable"

x-ref:
  "URL encoding leads to "400 - Bad Request""
  https://redmine.lighttpd.net/issues/946
  "400 Bad Request when using IP's numeric value ("ip2long()")"
  https://redmine.lighttpd.net/issues/1330

To allow most 8-bit and 7-bit chars in headers
  server.http-parseopt-header-strict  = "disable"  (not recommended)

x-ref:
  "Russian letters not alowed?"
  https://redmine.lighttpd.net/issues/602
  "header Content-Disposition with russian '?' (CP1251, ascii code 255) causes error"
  https://redmine.lighttpd.net/issues/1016