Pitch objective
some promising signs of improved spectrogram clarity:

![image](https://user-images.githubusercontent.com/6509132/215101429-c64267c2-e6d2-4cc5-9ad6-7392906daaf1.png)


summary of changes:
* model now has a first stage consisting of token and spectrogram encoders
* after the first stage an attention layer with a learned query vector is used to produce a "speaker encoding" from the spectrogram encodings
* The speaker encoding is added to the token encodings which are then used to predict token duration and pitch
* token encodings are then aligned with the spectrogram encodings, then run all together through the decoder