The PHP API is provided as a starting guide so that you can integrate it into multiple solutions. There are other methods to allow you to obtain the available streams on your Wowza server, but they would need customization as well.
For VOD streaming, you can create a module that queries the available files for a given application. This does require a Flash client, but you can convert it into an HTTPProvider so that you can call it as an HTTP request.
For live streaming, you can query either the REST API directly or the HTTPProvider to get a list of incoming streams. You will need to be able to parse the returned information or create a custom implementation based on the example source codes.