Reference NCrontab.Signed.nuspec in VS solution file

Author: atifaziz

NCrontab.sln

@@ -10,6 +10,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 		clean.cmd = clean.cmd
 		COPYING.txt = COPYING.txt
 		NCrontab.nuspec = NCrontab.nuspec
+		NCrontab.Signed.nuspec = NCrontab.Signed.nuspec
 		pack.cmd = pack.cmd
 		packw.cmd = packw.cmd
 		README.md = README.md