Removed some unnecessary classes
Added file chooser dialog and widgets related
Substituted old file chooser with new file chooser
Added fileChooserListener to constructor; some javadoc;
Converted fileComparator to private static class
Small bug fix saving FILE_CHOOSER_LAST_FOLDER preference
Properties renamed to .props to avoid encoding issues
Fixes single hardcoded .properties reference (in I18N)
Fixes a few bad encodings
Merge pull request #292 from manuel-freire/properties-to-props

Properties to props
Actions separated in two packages: model actions and editor actions
Added EditorAction and ModelActions, and associated controllers
Testing invalid arguments in actions
Added default mechanism to validate arguments
Created InvalidArgumentsException
Modified action constructors
Updated AddRecentGame
Updated ChangeLanguage
Updated editor actions to new signature
Updated model actions signature
Fix tests. Added some licenses.