Guard against a user not entering a / in the folder setting.

app/src/main/java/org/transdroid/daemon/DaemonSettings.java

@@ -122,7 +122,7 @@ public final class DaemonSettings {
 		return sslTrustKey;
 	}
 	public String getFolder() {
-		return folder;
+		return folder == null? null: (folder.startsWith("/")? folder: folder + "/");
 	}
 	public boolean shouldUseAuthentication() {
 		return useAuthentication;