Remove recommendation for installing as root

[threehams]

Reasons:

• npm, for a while, recommended never running as root, and instead suggested brew / brew + nvm / some other non-root method of installation.
• Nearly all other globally-installed npm packages don't include sudo as a recommendation.
• sudo doesn't exist on Windows.
• Installing Gluestick as root, while having a non-root Node installation, ends up mixing up permissions within the folder. Installing not as root will give a permissions error, and the user can add sudo to make it work. Overall, less damaging.

[christinebrass]

👍