Small config fixes

- fix import path
- remove unnecessary lines in webpack config
- remove unused file

docs/.gitattributes

@@ -1 +0,0 @@
-CHANGES.rst merge=union

src/headless/utils/core.js

@@ -8,12 +8,14 @@
 //
 /*global escape, Uint8Array */
 
+import * as strophe from 'strophe.js/src/core';
 import Backbone from "backbone";
 import Promise from "es6-promise/dist/es6-promise.auto";
-import { Strophe } from "strophe.js";
 import _ from "../lodash.noconflict";
 import sizzle from "sizzle";
 
+const Strophe = strophe.default.Strophe;
+
 
 /**
  * The utils object

webpack.config.js

@@ -164,8 +164,6 @@ function parameterize () {
                 "lodash.converter": "lodash.converter",
                 "lodash.noconflict": "lodash.noconflict",
                 "strophe": "strophe",
-                "strophe.ping": "strophe.ping",
-                "strophe.rsm": "strophe.rsm",
                 "window": "window"
             }],
             output: {