docs: primarily refer to schannel as WinSSL
conncache.c: fix possible dereference of null pointer
secureserver.pl: support for stunnel-path with nun-alphanum chars

This is desired to support stunnel installations on Windows.
Updated copyright year for recent changes
examples: Standardised username and password settings for all email examples

Replaced the use of CURLOPT_USERPWD for the preferred CURLOPT_USERNAME
and CURLOPT_PASSWORD options and used the same username and password for
all email examples which is the same as that used in the test suite.
ftp tests: provide LIST responses in the test file itself

Previously LIST always returned a fixed hardcoded list that the ftp
server code knew about, mostly since the server didn't get any test case
number in the LIST scenario. Starting now, doing a CWD to a directory
named test-[number] will make the test server remember that number and
consider it a test case so that a subsequent LIST command will send the
<data> section of that test case back.

It allows LIST tests to be made more similar to how all other tests
work.

Test 100 was updated to provide its own directory listing.
testcurl.pl: always show the last 5 commits even with --nogitpull