Includes docs and new test cases: 1525, 1526 and 1527

Co-written-by: Vijay Panghal

Without request body there's no point in asking for 100-continue.

Bug: http://curl.haxx.se/bug/view.cgi?id=1349
Reported-by: JimS

When doing passive FTP, the multi state function needs to extract and
use the happy eyeballs sockets to wait for to check for completion!

Bug: http://curl.haxx.se/mail/lib-2014-02/0135.html (ruined)
Reported-by: Alan

Since all present tests now have <keywords> listed, this script will now
refuse to run a given test case if no such section is provided.
Hopefully this will help us make sure new test cases get keywords added
at start.

In addition to commit fe260b75 fixed the same issue for RFC-821 based
SMTP servers and allow the credientials to be given to curl even though
they are not used with the server.

Reported-by: Melissa

Added SMTP (RFC-821 only) based test case as a reference for the fix
provided by commit fe260b75.

Follow up to 9317eced makes test 1056 work again.

This limitation was removed in commit 0bc4938e

Remove a superfluous "negotiated http2" info line

We're progressing throught drafts so there's no point in having a fixed
one in a symbol that'll survive.

This makes it possible to fetch from an IPv6 literal without specifying
the -g option.  Globbing remains available elsehwere in the URL.

For example:
  curl http://[::1]/file[1-3].txt



This creates no ambiguity, because there is no overlap between the
syntax of valid globs and valid IPv6 literals.  Globs contain hyphens
and at most 1 colon, while IPv6 literals have no hyphens, and at least 2
colons.

The peek_ipv6() parser simply whitelists a set of characters and counts
colons, because the real validation happens later on.  The character set
includes A-Z, in case someone decides to implement support for scopes
like [fe80::1%25eth0] in the future.

Signed-off-by: Paul Marks <pmarks@google.com>

As the second URL won't be passed input from stdin.

When the protocol part fails, the data usually does too but the protocol
part is often more fundamental and often provide the clues you need to
fix the test case.

Extended the regex to include other valid characters such as those used
in the reply text of Test 836.

As the email protocols implement SASL authentication rather than IMAP,
POP3 and SMTP specific authentication, updated the authentication
keywords to reflect this.

In the initializer for len, there is no prototype for "strlen".
In this statement, there is no prototype for "memcpy".

Added support for falling back to <data> when <data1>, <data2>, etc...
don't exist in the <reply> section of a unit test.