Updated for Swift 3

Process enum has been replaced with CommandLine in Swift 3. Changed main.swift to reflect this.

swift/main.swift

@@ -14,8 +14,8 @@ let items = [
 let app = GildedRose(items: items);
 
 var days = 2;
-if (Process.argc > 1) {
-    days = Int(Process.arguments[1])! + 1
+if (CommandLine.argc > 1) {
+    days = Int(CommandLine.arguments[1])! + 1
 }