* extract dom rendering from app_list.js to homescreen.js
Merge pull request #2 from dwi2/TV_arch1

[TV] Experimental IAC between system and homescreen
* rename app_list.js to applications.js
* modularize appList's view (separated from homescreen.js)
* don't use '?' to refresh the url in homescreenWindow
1. create hs_layout_editor which is a grid based layout engine
2. create widget editor which uses hs_layout_editor and shows a sample view of it.
3. relayout the html
Merge pull request #1 from huchengtw-moz/luke-tv-arch-1-widget

Link widget editor and homescreen.
* add "AppList.prototype.oniconclick" hook method
* change oniconclick callback parameter
* change "Applications.getIconURL" to "Applications.getIconBlob"
* change oniconclick callback parameter (again)
add selection border and use it in widget editor.
Merge pull request #3 from huchengtw-moz/luke-tv-arch1-widget-editor-border

add selection border and use it in widget editor.
[Widget] Create 2048 widget
Merge pull request #4 from shamenchens/TV_arch1

[Widget] Create 2048 widget
link widget editor and app list.
Merge pull request #5 from huchengtw-moz/luke-tv-arch1-widget-add-app

link widget editor and app list.
fix bugs:
1. when widget editor is visible, we don't need to rerun the code of visible
2. handle the case of no-icon app
3. don't call switch focus when user press enter
4. don't handle keyevent when applist is shown
Merge pull request #6 from huchengtw-moz/luke-tv-arch1-widget-bug-fixing

fix bugs
[Widget] Create clock widget
Merge pull request #7 from shamenchens/TV_arch1

[Widget] Create clock widget
* add vendor/evt.js
* appList paging mechanism (WIP)