Add hyper theme

[tani]

Hi there,

Thank you for inventing the great colour palette. As I know that your repository has already had a hyper theme but it looks incomplete for the following points. Thus, I created an alternative https://github.com/tani/hyper-rigel .

• hyper-rigel is not uploaded on npmjs.com
• only available 8 colours.
• no colour configuration for selection.

If you would not mind merging my repository to your project, and use npmjs.com namespace. Please tell me.
I can send the PR and transfer the package name to your account.