* Refactor `TouchHandler` to handle double-tap and swipe gestures.
* Renamed existing `onTouch` JavaScript methods to `onItemTouch` and
added `onContentTouch` methods for swipe gesture.
* Refactor double-tap. It's now a method in `TouchHandler` versus
anonymous functions in `listen()` method.
* Updated CSS classes.
* Added `touch-action` CSS for `.entry-content`.
* Renamed CSS classes for adding events in `TouchHandler`.
* Updated users settings to replace checkbox for double tap with select
for none, double tap, or swipe.
* Added database migrations for new gesture_nav option.
* Rename `users.double_tap` to `users.gesture_nav` and migrate
existing user settings.
* Updated translation files. (Non-English updated with Google
Translate.)
Resolves#1449, closes#1495
Firefox autocompletes the password field (but not the password
confirmation field) for me. This makes it annoying to use the settings
page, because miniflux thinks I'm trying to change my password and
complains that the fields don't match.
