FileInfo = { 'rewriteUrls' - option - whether to adjust URL's to be relative 'filename' - full resolved filename of current file 'rootpath' - path to append to normal URLs for this node 'currentDirectory' - path to the current file, absolute 'rootFilename' - filename of the base file 'entryPath' - absolute path to the entry file 'reference' - whether the file should not be output and only output parts that are referenced
function(less, context, rootFileInfo) {
        this.less = less;
        this.rootFilename = rootFileInfo.filename;
        this.paths = context.paths || [];  // Search paths, when importing
        this.contents = {};             // map - filename to contents of all the files
        this.contentsIgnoredChars = {}; // map - filename to lines at the beginning of each file to ignore
        this.mime = context.mime;
        this.error = null;
        this.context = context;
        // Deprecated? Unused outside of here, could be useful.
        this.queue = [];        // Files which haven't been imported yet
        this.files = {};        // Holds the imported parse trees.
    }