CRLF adjustment
Added unit test for PacketBuilder.CreateAuthenticationHeader
Rewrote PacketBuilder.CreateAuthenticationHeader so it uses String.Format instead of string concatenation and added a dynamically created UserAgent property so the version number can be fetched from assembly metadata instead of being hard coded.
Fetch the UserAgent from PacketBuilder instead of hard coding it in RavenClient's HTTP request.
Updated test so it validates the correct data.
Changed the naming convention for private static fields to lowerCamelCase.
Added documentation to PacketBuilder's static constructor and made the userAgent field readonly.
Made SentryVersion a const so it's easier to change.
Merge pull request #43 from asbjornu/unit-testing

Added unit test for the PacketBuilder.CreateAuthenticationHeader and rewrote its internals so the assembly's version number is used instead of a hard coded value. The assembly's version number is also used in the HTTP request's UserAgent header.