term: remove redundant events of inputHelper and redundant contentEditable

We do not need to listen for keydown and keypress for inputHelper because these events will propagate through the parent.
Listening them will be redundant and will cause some shortcut key combinations to stop working.

Since we now have a hidden `textarea`, there is no longer need to set anything to contentEditable

coffees/ext/popup.coffee

@@ -9,10 +9,6 @@ class Popup
     @el.innerHTML = html
     @el.classList.remove 'hidden'
 
-    # ff glorious hack
-    if typeof InstallTrigger isnt "undefined"
-      document.body.contentEditable = 'false'
-
     addEventListener 'click', @bound_click_maybe_close
     addEventListener 'keydown', @bound_key_maybe_close
 
@@ -20,10 +16,6 @@ class Popup
     removeEventListener 'click', @bound_click_maybe_close
     removeEventListener 'keydown', @bound_key_maybe_close
 
-    # ff glorious hack
-    if typeof InstallTrigger isnt "undefined"
-      document.body.contentEditable = 'true'
-
     @el.classList.add 'hidden'
     @el.innerHTML = ''
 

coffees/term.coffee

@@ -119,10 +119,6 @@ class Terminal
       @compositionUpdate.bind(@)
     @inputHelper.addEventListener 'compositionend',
       @compositionEnd.bind(@)
-    @inputHelper.addEventListener 'keydown',
-      @keyDown.bind(@)
-    @inputHelper.addEventListener 'keypress',
-      @keyPress.bind(@)
     addEventListener 'keydown', @keyDown.bind(@)
     addEventListener 'keypress', @keyPress.bind(@)
     # Always focus on the inputHelper textarea