dist: include the projects/ files in releases

... the recent MSVC project files added by Steve Holme
sas: Added DIGEST-MD5 qop-option validation in native challange handling

Given that we presently support "auth" and not "auth-int" or "auth-conf"
for native challenge-response messages, added client side validation of
the quality-of-protection options from the server's challenge message.
build: Added Visual Studio 2008 (VC9) project files

Carrying on from commit 11025613b9, added VC9 project files which are
capable of supporting side-by-side compilation, 32-bit and 64-bit
builds as well as support for some of the third-party libraries curl
uses.