js: typecheck destructured parameters

• destructuring just takes the input argument and treats it as object. In cases like in src/Keyring/generateKey, where I forgot to change the old syntax, the fingerprint as string was destructured into an object without "pattern", which caused all Keys to be retrieved. So, methods with a destructuring now check if the first argument is an object and get a default empty object if no parameter is submitted. This allows the further use of destructured parameters, while still ensuring nothing vastly incorrect is used.
• src/Kering.js, unittsets.js: fixed old syntax in method usage