Added implementation to the getVendorPrefixes function of property.js. Added to the cleanseRuleSetData function of jCss.js to add in the vendor prefixes
Added isVendorPrefixed function to property.js to determine whether the user has added their own vendor prefixing. These will be removed and readded later. This is a bit opinionated but works well because it will group all prefixes together and in the correct order