Add W&B embedding projector example

[scottire]

Hi,

I've added an example showing how to use the Weights & Biases embedding projector with OpenAI embeddings. Let me know if there's anything I can change to help it get merged.

Here's an example that was created by it: http://wandb.me/openai_embeddings You can dynamically change what dimensionality reduction algorithm is used, along with choosing which of your logged data is shown with color & hover.