refactor selector parser wrapper

Author: eush77

index.js

@@ -1,6 +1,6 @@
 'use strict';
 
-var parseSelector = require('./lib/selector')(),
+var parseSelector = require('./lib/selector'),
     select = require('./lib/select');
 
 var debug = require('debug')('unist-util-select');

lib/selector.js

@@ -3,10 +3,10 @@
 var Parser = require('css-selector-parser').CssSelectorParser;
 
 
-module.exports = function SelectorParser () {
+module.exports = function parseSelector (selector) {
   var parser = new Parser;
   parser.registerNestingOperators('>', '+', '~');
   parser.registerAttrEqualityMods('^', '*', '$');
   parser.registerSelectorPseudos('not');
-  return parser.parse.bind(parser);
+  return parser.parse(selector);
 };