Add some ESLint rules + minor changes (#3665)

Main point was to enable ESLint `dot-notation` and `no-unneeded-ternary`
rules for more code consistency.

I took the occasion to add two minor commits:
- Fix a problem found by running `test:spelling
- Minor dependency update

It wouldn't be a problem if the PR didn't arrive in the next release,
the changes are cosmetic.

clientonly/index.js

@@ -28,7 +28,7 @@
 		});
 
 		// determine if "--use-tls"-flag was provided
-		config["tls"] = process.argv.indexOf("--use-tls") > 0;
+		config.tls = process.argv.indexOf("--use-tls") > 0;
 	}
 
 	/**