Initial js app - moves existing js code from layout to the app.js file and adds a single owl slider

install using bower, compile using grunt

Signed-off-by: Josh Angell <jbangell@gmail.com>
Merge branch 'issues/599-gh-pages-redesign' of github.com:mysociety/fixmystreet into issues/599-gh-pages-redesign

Signed-off-by: Josh Angell <jbangell@gmail.com>

Conflicts:
	_layouts/default.html
	assets/css/global.min.css
remove page-wrapper div

Signed-off-by: Josh Angell <jbangell@gmail.com>