Create cssinject.js

Added a CSS injector bookmarklet.  Make a bookmark in your browser and paste this script into the "url" field.  

Upon clicking the bookmarklet, enter the URL of where your stylesheet is (that you want to inject).  Optionally, you may enter an interval (in seconds), upon which the stylesheet will be reinjected into the page.  

This is useful if you are making live edits to the stylesheet and want to keep seeing the changes refreshing on the target site.

Developed this for a friend and figured it could be useful for others to use.  Hope you enjoy.