Merge pull request #2031 from chenboxiang/master

Fix a bug: if the less file end line is comments, the lessc command option "modify-var" will have no effect.

bin/lessc

@@ -336,7 +336,7 @@ var parseLessFile = function (e, data) {
         return;
     }
 
-    data = options.globalVariables + data + options.modifyVariables;
+    data = options.globalVariables + data + '\n' + options.modifyVariables;
 
     options.paths = [path.dirname(input)].concat(options.paths);
     options.filename = input;