Revert "Merge pull request #4254 from astaxie/develop-2.0"

This reverts commit e284b0ddae, reversing
changes made to 8ef8fd2606.

adapter/utils/captcha/README.md

@@ -1,45 +0,0 @@
-# Captcha
-
-an example for use captcha
-
-```
-package controllers
-
-import (
-	"github.com/astaxie/beego"
-	"github.com/astaxie/beego/cache"
-	"github.com/astaxie/beego/utils/captcha"
-)
-
-var cpt *captcha.Captcha
-
-func init() {
-	// use beego cache system store the captcha data
-	store := cache.NewMemoryCache()
-	cpt = captcha.NewWithFilter("/captcha/", store)
-}
-
-type MainController struct {
-	beego.Controller
-}
-
-func (this *MainController) Get() {
-	this.TplName = "index.tpl"
-}
-
-func (this *MainController) Post() {
-	this.TplName = "index.tpl"
-
-	this.Data["Success"] = cpt.VerifyReq(this.Ctx.Request)
-}
-```
-
-template usage
-
-```
-{{.Success}}
-<form action="/" method="post">
-	{{create_captcha}}
-	<input name="captcha" type="text">
-</form>
-```