add global options css for query

like `babel` :  https://github.com/babel/babel-loader/blob/master/index.js#L36

Author: helloyou2012

lib/loader.js

@@ -3,6 +3,7 @@
 	Author Tobias Koppers @sokra
 */
 var path = require("path");
+var assign = require('object-assign');
 var loaderUtils = require("loader-utils");
 var processCss = require("./processCss");
 var getImportPrefix = require("./getImportPrefix");
@@ -12,7 +13,9 @@ var compileExports = require("./compile-exports");
 module.exports = function(content, map) {
 	if(this.cacheable) this.cacheable();
 	var callback = this.async();
-	var query = loaderUtils.parseQuery(this.query);
+	var globalOptions = this.options.css || {};
+	var loaderOptions = loaderUtils.parseQuery(this.query);
+	var query = assign({}, globalOptions, loaderOptions);
 	var root = query.root;
 	var moduleMode = query.modules || query.module;
 	var camelCaseKeys = query.camelCase || query.camelcase;