Advanced Error Handling

Hi,

in my app it's not always guaranteed, that the URL for streaming is still available. Therefore I somehow need to know when AndroidVideoCache fails to open the URL. It would be cool, if you didn't catch the exceptions, but throw them, so we can try/catch them ourselves. So for example `proxy.getProxyUrl(url);` throws `ProxyCacheException`. Or is there another way you suggest? I don't want to `HEAD` request the resource first, just to check if it's available.

Any ideas? Thanks!