templates: Converted statistics pages to Jinja2
templates: Converted tracking info page to Jinja2
templates: Simplified i18n title messages including links
templates/flights: Fixed registration/competition id escaping
templates: Removed Genshi remains from details-table.jinja
templates: Added more strings to i18n
setup.py: Added encoding and extensions to Jinja2 i18n extraction config
templates/flights/nav: Added "All Flights" to i18n strings
templates/clubs: Converted clubs list to Jinja2
templates/clubs: Converted club details page to Jinja2
templates/users: Converted details page to Jinja2
templates/macros/datetime: Removed Genshi remains
templates/macros/datetime: Fixed whitespace stripping
model/notification: Added constants() method

Returns a dict with all constants (uppercase class members) defined by
this class.
templates/notifications: Converted notification list to Jinja2