Merge: Benitlux: Improve the iOS variation and general bug fixes

General improvements to Benitlux:
* Don't suggest to follow current friends.
* Don't allow to post a review when not logged in.
* Forget current login on an invalid token and don't recheck them.
* Extract the manual button for checking in and out to its own module.
* Use more precise classes to offer more variation points for platform adaptations.

Improvements to the look on iOS:
* Rely on the new default behavior of the iOS implementation of *app.nit* to ellipsize long texts.
* Less auto correct and auto capitalizing.
* Use placeholder text to identify text fields.
* Prettier views and windows in general, more alignment, text color, sizes, etc.
* Fix icon when the font is missing.

See the result for yourself!
![Benitlux on iOS](http://xymus.net/pub/ben-ios.png)

Pull-Request: #2352