I18n Support (#72)

* adapt UI for i18n

* add placeWidgets() helper function to ease translation

* add hint about Transition Matrix plugin on Transition tab

* translate

* rework UI of file tab

* write status of plugin to scene info file

src/headers/switch-executable.hpp

@@ -40,9 +40,5 @@ private:
 	QComboBox *processes;
 	QCheckBox *requiresFocus;
 
-	QLabel *whenLabel;
-	QLabel *switchLabel;
-	QLabel *usingLabel;
-
 	ExecutableSwitch *switchData;
 };