New authentication code added, particularly noticable when doing POST or PUT

with Digest or NTLM. libcurl will now use HEAD to negotiate the authentication
and when done perform the requested POST.

tests/data/test157

@@ -0,0 +1,38 @@
+# Server-side
+<reply>
+<data>
+HTTP/1.1 200 No Authorization Required swsclose
+Server: Apache/1.3.27 (Darwin) PHP/4.1.2
+Content-Type: text/html; charset=iso-8859-1
+Connection: close
+
+GET received and served just fine. Thank you very much
+</data>
+</reply>
+
+# Client-side
+<client>
+<server>
+http
+</server>
+ <name>
+HTTP GET with --anyauth (when the server requires none)
+ </name>
+ <command>
+http://%HOSTIP:%HOSTPORT/157 -u testuser:testpass --anyauth
+</command>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+<strip>
+^User-Agent:.*
+</strip>
+<protocol>
+GET /157 HTTP/1.1
+Host: 127.0.0.1:8999
+Pragma: no-cache
+Accept: */*
+
+</protocol>
+</verify>