This makes the tests easier to copy and relocate to other test numbers
without having to update content.

Closes #6738

missing CRs and modified %hostip

lib556/test556: use a real HTTP version to make test reuse more convenient

make sure the weekday in Date headers matches the date

test61: replace stray "^M" (5e 4d) at the end of a cookie with a '^M' (0d)

Gets the test working with external proxies like Privoxy again.

Closes #6463

... so that we can check HTTP requests for User-Agent: curl/%VERSION

Update 600+ test cases accordingly.

Closes #6037

Each shows evidence of flakiness on at least one platform on
the autobuilds. Users can use this keyword to skip these tests
if desired.

According to RFC 2616 and RFC 2326 individual protocol elements, like
headers and except the actual content, are terminated by using CRLF.

Therefore the test data files for these protocols need to contain
mixed line-endings if the actual protocol elements use CRLF while
the file uses LF.

Dirk Manske reported a regression. When connecting with the multi
interface, there were situations where libcurl wouldn't store
connect time correctly as it used to (and is documented to) do.

Using his fine sample program we could repeat it, and I wrote up
test case 573 using that code. The problem does not easily show
itself using the local test suite though.

The fix, also as suggested by Dirk, is a bit on the ugly side as
it adds yet another call to Curl_verboseconnect() and setting the
TIMER_CONNECT time.  That situation is subject for some closer
inspection in the future.