Updated the coding style, in this function, to be consistent with other
response functions rather then performing a hard return on failure.

Standardised the naming of all perform based functions to be in the form
pop3_perform_something() following the changes made to IMAP.

Started to apply the same tidy up to the POP3 code as applied to the
IMAP code in the 7.30.0 release.

Added support for specifying the preferred authentication mechanism in
the URL as per Internet-Draft 'draft-earhart-url-smtp-00'.

... to use left-shifted values, like those defined in curl.h, rather
than 16-bit hexadecimal values.

Added support for specifying the preferred authentication type and SASL
mechanism in the URL as per RFC-2384.

Added support for specifying the preferred authentication mechanism in
the URL as per RFC-5092.

... to use left-shifted values, like those defined in curl.h, rather
than 16-bit hexadecimal values.

In preparation for the upcoming changes to IMAP, POP3 and SMTP added
preferred mechanism values.

As well as parsing the username and password from the URL, added support
for parsing the optional options part from the login details, to allow
the following supported URL format:

schema://username:password;options@example.com/path?q=foobar

This will only be used by IMAP, POP3 and SMTP at present but any
protocol that may be given login options in the URL will be able to
add support for them.

warning: unused variable 'smtp' introduced in commit 73cbd21b.

...instead of the 220 we otherwise expect.

Made the ftpserver.pl support sending a custom "welcome" and then
created test 1219 to verify this fix with such a 230 welcome.

Bug: http://curl.haxx.se/mail/lib-2013-02/0102.html
Reported by: Anders Havn

For libc variants without a spearate pthread lib (like bionic), try
using pthreads without the pthreads lib first and only if that fails try
the -lpthread linker flag.

Bug: http://curl.haxx.se/bug/view.cgi?id=1216
Reported by: Duncan

Accessing a file with an absolute path in the root dir but with no
directory specified was not handled correctly. This fix comes with four
new test cases that verify it.

Bug: http://curl.haxx.se/mail/lib-2013-04/0142.html
Reported by: Sam Deane

This ought to speed up additional TLS handshakes, at least in theory.

Moved imap_is_bchar() be with the other utility based functions.

Moved imap_parse_url_path() and imap_parse_custom_request() to the end of the
file allowing all utility functions to be grouped together.

Moved imap_atom() and imap_sendf() to the end of the file allowing all
utility functions to be grouped together.

... in case runtests.pl is invoked with non-default -b option

Fixes a regression caused by 1e29d275.

Update sharing interface documentation to provide exhaustive list of
what it does and does not share.

Most notable the security advisory:
http://curl.haxx.se/docs/adv_20130412.html

... and make 1216 also verify it with a file input

These tests verify commit 3604fde3d3c9b0d, the fix for the "cookie
domain tailmatch" vulnerability. See
http://curl.haxx.se/docs/adv_20130412.html

Cookies set for 'example.com' could accidentaly also be sent by libcurl
to the 'bexample.com' (ie with a prefix to the first domain name).

This is a security vulnerabilty, CVE-2013-1944.

Bug: http://curl.haxx.se/docs/adv_20130412.html

The previously applied patch didnt work on Windows; we cant rely
on shell commands like 'echo' since they act diffently on each
platform and each shell.
In order to keep this script platform-independent the code must
only use pure Perl.