[PreviewView] Populate all pages to thumbnails (layout to be fixed)

also done:
[app.js]: added App.model to make the model exposable
[editViewController] fixed components handlers after new page
[storyModel]: fixed addPage()
Merge branch 'master' of https://github.com/Group6-Lab4/FinalProject

Conflicts:
	index.html
	js/controller/editViewController.js
	js/model/storyModel.js
	js/view/previewView.js
Merge branch 'master' of https://github.com/Group6-Lab4/FinalProject

Conflicts:
	index.html
	js/controller/editViewController.js
	js/model/storyModel.js
	js/view/previewView.js