Added language switcher.

 * Language switcher will display all languages (in the current language) in a dropdown on the main menu.
 * Language icons are taken from the set at http://www.famfamfam.com/lab/icons/flags/
 * Load the Google Maps API in the correct language.
 * Do not localize map coordinates, as they are fed into the directions API.
Merge pull request #129 from dzwarg/language-switcher

Added language switcher.