Adding build number label for TeamCity builds
Added more convenient setup of throwing exceptions.

Instead of _something.When(s => s.DoStuff()).Do(ci => { throw new ArgumentException(); }), just call _something.When(s => s.DoStuff()).Throw<ArgumentException>().
Throw<Exception>() returns exception for easy verification.
Fix xmldoc typo
Updating changelog/breaking changes for 1.8.0 release
Update nuget to 2.8.3
Update website for 1.8.0 release
Fixing 1.8.0.0 web site download link