[Refactor] Make the app routes static methods

They don’t use self, so PyLint complains.

calsocial/__init__.py

@@ -106,8 +106,9 @@ class CalendarSocialApp(Flask):
 
             self.route(*args, **kwargs)(attr)
 
+    @staticmethod
     @route('/')
-    def hello(self):
+    def hello():
         """View for the main page
 
         This will display a welcome message for users not logged in; for others, their main
@@ -128,8 +129,9 @@ class CalendarSocialApp(Flask):
 
         return render_template('index.html', calendar=calendar)
 
+    @staticmethod
     @route('/register', methods=['POST', 'GET'])
-    def register(self):
+    def register():
         """View for user registration
 
         If the ``REGISTRATION_FAILED`` configuration value is set to ``True`` it displays the
@@ -156,9 +158,10 @@ class CalendarSocialApp(Flask):
 
         return render_template('registration.html', form=form)
 
+    @staticmethod
     @route('/new-event', methods=['GET', 'POST'])
     @login_required
-    def new_event(self):
+    def new_event():
         """View for creating a new event
 
         This presents a form to the user that allows entering event details.