[refactoring] rename list view layout
[refactoring] reactivate on click handler
[refactoring] list element handling
[refactoring] internal data structure
[refactoring] check file extension
[refactoring] rename member, remove TODO
[refactoring] add ListAdapterCartridges
[refactoring] rename base class
[refactoring] reactivate assignment statements
[bugfix] reactivate update() method
[refactoring] work with YCartridge objects not with URIs
[refactoring] remove unused code
[refactoring] handling data at adapter
[bugfix] show cartridge details
[improvement] change background color
[refactoring] change log method
[refactor] change TAG content
[refactoring] remove member mContext, set member mActivity protected
[bugfix] check if a saved game already exists
[bugfix] insert onDestory method to avoid memory leaks