simple popup templates with no styling; 

Couldn't add i18n translations due to rubygems outage this evening :(.

Sure these popups are 100% Krakow specific, but I guess there is no point to going too general right now. Still, they will help us with further development as they show what's inside the features downloaded from the server.
Maybe this class can be renamed into `Popup` with "constructor" instead of `bindPopup` method and template can be property of something like `KrakowPlanLayer` class (e.g as a `popupTemple` method). As a conclusion we will have generic way to show popups and `Popup` will not validate [Single responsibility principle](http://en.wikipedia.org/wiki/Single_responsibility_principle).