StandaloneFilterWindow is Broken

It's a full stop if either JucePlugin_MaxNumInputChannels or JucePlugin_MaxNumOutputChannels aren't defined.

Something needing updating as per the latest bus changes, I presume?

https://github.com/julianstorer/JUCE/blob/master/modules/juce_audio_plugin_client/Standalone/juce_StandaloneFilterWindow.h#L75-L85

Fixed!