Change tour-display style, add helper message.

Add:
	templates/index.html, static/css/index.sass, index.js
		-add helper message to front page, with necessary styling and animation.

Mod:
	templates/(profile, premade_tours).html
		-instead of displaying existing tours in columns of two, display them in
		a single centered column.

	app.py
		-a message submission from the contact page now redirects the user to
		the home page, as opposed to returning him/her to the contact page --
		seems more intuitive.