Don't stop installing applications after a failure

mas-cli/Commands/Install.swift

@@ -12,13 +12,27 @@ struct InstallCommand: CommandType {
     let function = "Install from the Mac App Store"
     
     func run(options: Options) -> Result<(), MASError> {
-        for id in options.appIds {
+        // Try to download applications with given identifiers and collect results
+        let results = options.appIds.map { (id) -> Result<(), MASError> in
             if let error = download(id) {
                 return .Failure(error)
+            } else {
+                return .Success()
             }
         }
-
-        return .Success(())
+        // See if at least one of the downloads failed
+        let errorIndex = results.indexOf {
+            if case .Failure(_) = $0 {
+                return true
+            }
+            return false
+        }
+        // And return an overrall general failure if there're failed downloads
+        if let _ = errorIndex {
+            return .Failure(MASError(code: .DownloadFailed))
+        } else {
+            return .Success()
+        }
     }
 }