app_back api: provide `connect`, add own middlewares there
App.backend: fix 3417c5391f752c83340c96b89137b4c9353a421d
ServerResponse: `res.js()` send components or arbitrary JS to UI front
first authorized back + front loading: `App.backend.JS`

* App.backend.Connection: move `App.backend.JS` in its `pingback.js` module
* pingback: provide JS code for UI, if allowed
  Note: `userman` runs before `pingback` and handles auth in mwBasicAuthorization()
* if unauthorized set res.statusCode = 401
* App.cfg.extjs.require: app modules fill this cfg item; UI on auth must do:
    Ext.require(App.cfg.extjs.require)
  or better sync:
    Ext.Loader.syncRequire(App.cfg.extjs.require)

  any css && stuff loading must be provided here as JavaScript

* fix config: disable `procman`, there is no such app module yet

= tested in devtools: =

App.backend.req({url:'login', params:'olecom\npassmd5\ndeveloper'})
> Object {id: 2, xhr: XMLHttpRequest, headers: Object, options: Object, async: true…}
App.backend.req({url:'auth', params:'olecom\npassmd5\ndeveloper'})
> Object {id: 3, xhr: XMLHttpRequest, headers: Object, options: Object, async: true…}
Ext.require(App.cfg.extjs.require)
> Object {isInHistory: Object, history: Array[9], config: Object, setConfig: function, getConfig: function…}
App.backend.wait_events()
> Object {id: 4, xhr: XMLHttpRequest, headers: Object, options: Object, async: true…}
var f = '(' + (function server(){ req.waits[req.sessionID].json('all is ok!!!') } ).toString() + ')()'
App.backend.JS(f)
> undefined
> Object
>    success: true                         JS.js?_dc=1395826225993:15
> `App.backend.JS.res` has this `Object`   JS.js?_dc=1395826225993:16