Continued code implementation of eigenverb models.
- Added new bool matrix to wave_queue_reverb to keep track of invalid rays on the wavefront
- Added code before notify calls in reflection_model and detect_volume_reflections, to prevent the use of invalid rays
- Added accessor to _invalid_ray
- virtualized detect_reflections, as when using wave_queue_reverb, the overloaded function is needed
- Added new checks inside of various reverberation code to check for volume_layers, and skip portions if not present
- Added another check in the notify calls to only add the eigenverb if the intensity of the ray is greater then 1e-20