added shortcut manager and allow user to customize toggle mode shortcut

browser/main/index.js

@@ -9,7 +9,6 @@ import { syncHistoryWithStore } from 'react-router-redux'
 require('./lib/ipcClient')
 require('../lib/customMeta')
 import i18n from 'browser/lib/i18n'
-import ee from 'browser/main/lib/eventEmitter'
 
 const electron = require('electron')
 
@@ -64,12 +63,6 @@ document.addEventListener('keyup', function (e) {
   }
 })
 
-document.addEventListener('keydown', function(e) {
-  if (e.key === 'm' && e.ctrlKey) {
-    ee.emit('topbar:togglemodebutton')
-  }
-});
-
 document.addEventListener('click', function (e) {
   const className = e.target.className
   if (!className && typeof (className) !== 'string') return