Modify form to use WTForms, with regex validation

- Doesn't do anything with nonvalid inputs yet

	modified:   weather_app/forms.py
	modified:   weather_app/www/routes.py
	modified:   weather_app/www/templates/index.html

Conflicts:
	weather_app/forms.py
	weather_app/www/routes.py
CHECKPOINT Add error messages to input form

	modified:   weather_app/forms.py
	modified:   weather_app/www/templates/index.html