Remove HTTP_PARSER_DEBUG macro.

Remove the HTTP_PARSER_DEBUG macro for two reasons:

* It changes the size of struct http_parser, resulting in spurious memory
  corruption bugs if part of your application is built with HTTP_PARSER_DEBUG=1
  and other parts with HTTP_PARSER_DEBUG=0.

* It's a debugging tool for maintainers. It should never have been exposed in
  the API in the first place.
test: use error-checking strncat/strncpy replacements
test: fix buffer overflow in large header test

Fixes #136.
Fix IPv6 address parsing.

Fixes #133.
Update AUTHORS
Fix unmatched quote in dump_url output.
Fix MSVS 2005 and 2008 missing size_t typdef.

Replace manual size_t typedef with stddef.h include

Fixes #128, #141.
Update AUTHORS
Add a simple utility to dump events as they happen
Add on_status_complete callback.

Add a "status complete" callback to support Simple-Response handling with HTTP
version <= 1.0.

Patch by Tóth Tamás, tests by Corey Richardson.
Update AUTHORS and .mailmap
Move url_parser.c to contrib/
doc: add travis build status link
Update AUTHORS and .mailmap
Bump to version 2.1
build: set SONAME in shared object file

Fixes #151.