Make javascript and style links relative

Hey folks,

Based on our conversation today I thought this would be helpful. Adding relative links to javascript and style links is done this way so it doesn't rely on concatenating the plugin's folder name. (I also updated the README in this commit since users won't need to worry about the name of the folder). Feel free to test and accept if it's useful for you all. I tested this on a clean install with a plugin folder different from the original scheme and everything seemed to operate normally.