Added welcome message in Spanish, Catalan, Galician and Basque
Had pushed the message commented out
Merge pull request #24 from python-spain/welcome-message

Welcome message
Typos fixed
Alert or success message on newsletter subscription form

- Meaningful HTTP responses
- Set content type to JSON
- Move scripts to the end of the page for faster page load

Missing styles.
Fix indentation
Merge branch 'subscription' of github.com:python-spain/pycones-web into subscription