tried a couple minor adjustments to get SASS working
Merge branch 'dev_story-transitions' of https://github.com/TelegraphCreative/tibetanstories-FED into dev_story-transitions

Conflicts:
	assets/css/app.css
	config.rb

conflicts resolved using theirs
added the framework to manage the interactions
	- dynamic story discovery
	- URL hashchange triggering
	- prev/next management
	- class adding/removing during animations
added two story sections to the index for testing purposes - included new css and js files
added transition animations that match the desired effect