Missing Azure SDK on buildserver made builds fail

The inclusion of the Microsoft.Windows.Azure.targets file has been made
conditional so that the Glimpse.WindowsAzure.Sample project is only
built when used locally or at least when the
Microsoft.Windows.Azure.targets file is available.
Merge branch 'master' into no700-handle-possible-validation-failures-when-serializing-form-or-querystring-values