Fix sergent

[bcipolli]

Things were so darn slow running locally, I investigated two places where we were computing network outputs from scratch.

• Updated main de_DE script, to only compute hidden unit outputs if needed (for perceptron training).
• Removed computation of outputs from Sergent analysis code. They weren't doing proper z-scoring of the data anyway.

This does change the sergent results, so those need to be re-run.