This class can merge and minify and JavaScript and CSS files. It can compress JavaScript and CSS files by stripping unnecessary comments, spaces, tabs and line breaks. Previously minified images are skipped. The Javascript processing can use JSMin or the Google Closure API. The class can also merge multiple JavaScript and CSS files to minimize the number of server requests. External images used by CSS files may be converted to be inserted in the CSS styles using data URLs. The class caches processed files to avoid processing overhead until any of the source files is changed.