Add custom navigation guard to settings page (#137)

Closes: #131

There is probably a better ("more native") way to do this, but I spent hours trying to figure it out and in the end it was way easier to circumvent the built-in f7 router events and just use my own custom back button. D.U.M. - dumb, but not my fault (I think...).

Signed-off-by: Justin Georgi <justin.georgi@gmail.com>

Reviewed-on: #137

src/js/routes.js

@@ -27,7 +27,7 @@ var routes = [
   },
   {
     path: '/settings/',
-    component: SettingsPage,
+    component: SettingsPage
   },
   {
     path: '/contact/',