restructure internal indexes a bit

lib/6to5/browser.js

@@ -1,6 +1,6 @@
 "use strict";
 
-var transform = module.exports = require("./transformation/transform");
+var transform = module.exports = require("./transformation");
 
 transform.version = require("../../package").version;
 

lib/6to5/detection/index.js

@@ -4,7 +4,7 @@ var useragent = require("useragent");
 var traverse  = require("../traverse");
 
 var SYNTAX_KEYS = require("./syntax-keys");
-var visitors    = traverse.explode(require("./detect-visitors"));
+var visitors    = traverse.explode(require("./visitors"));
 
 function detect(ast) {
   var stats = {

lib/6to5/file.js

@@ -4,8 +4,8 @@ module.exports = File;
 
 var SHEBANG_REGEX = /^\#\!.*/;
 
-var transform  = require("./transformation/transform");
-var generate   = require("./generation/generator");
+var transform  = require("./transformation");
+var generate   = require("./generation");
 var clone      = require("./helpers/clone");
 var Scope      = require("./traverse/scope");
 var util       = require("./util");

lib/6to5/index.js

@@ -1,6 +1,6 @@
 "use strict";
 
-var transform  = require("./transformation/transform");
+var transform  = require("./transformation");
 var util       = require("./util");
 var fs         = require("fs");
 var isFunction = require("lodash/lang/isFunction");