Fix zip.workerScriptsPath backward compatibility issue and deprecate zip...

Fix zip.workerScriptsPath backward compatibility issue and deprecate zip workerScriptsPath.
> `workerScriptsPath` is supported with this PR. I just object the idea of use workerScriptsPath and workerScripts together. 

You don't *have to* use both. I just want to avoid unnecessarily breaking applications when users upgrade zip.js. 

> If the expected behavior is just "concatenate workerScriptsPath with workerScripts.inflater|deflater[0]", users can just put the result of concatenation to workerScripts.inflater|deflater[0], why bother to set workerScriptsPath?
> Some users may even wrongly expect url-resolving behavior, and will find that zip.js sometimes works and sometimes not.

That's why the properties are documented... String concatenation is clearly defined. Supporting concatenation comes at no cost (because the option has been around long before you submitted your original PR), so we can as well document it and keep future support for it.

Here's a possible use case:

```
obj.zip.workerScriptsPath = app.baseURL; // set elsewhere by a build to, e.g. /js/dist-v3.1.1/
obj.zip.workerScripts = [ 'zipjs-worker.min.js' ]; // Always the same
```