freeaddrinfo to the trace output

with CURLOPT_PROXY can use a http:// prefix and user + password. The user
and password fields are now also URL decoded properly.

Test case 264 added to verify.

address was not possible to use. It is now, but requires it written
RFC2732-style, within brackets - which incidently is how you enter numerical
IPv6 addresses in URLs. Test case 263 added to verify.

binary zeroes within the headers. They confused libcurl to do wrong so the
downloaded headers become incomplete. The fix is now verified with test case
262.

talking to sockfilt

can't be opened

to the docs.

"http://somehost?data" as it added a slash too much in the request ("GET
/?data/"...). Added test case 260 to verify.

or the test is skipped. Ideally, we should let this test case go over a few
frequently used IPv6 localhost aliases...

Added resolve.c to simply resolve a given host name

A) Normal non-proxy HTTP:

 - no more "Pragma: no-cache" (this only makes sense to proxies)

B) Non-CONNECT HTTP request over proxy:

 - "Pragma: no-cache" is used (like before)
 - "Proxy-Connection: Keep-alive" (for older style 1.0-proxies)

C) CONNECT HTTP request over proxy:

 - "Host: [name]:[port]"
 - "Proxy-Connection: Keep-alive"

but we could use having a look at ares/config.h when that is used

HTTP test server is a bit limited though, as it never responds to the POST
request until all data has been sent (and received)...

download a file from the server before the server is considered fine to use
for the given test case. This should fix the cases where the server can run
but curl cannot work with it.