Added doxgen comments to filesyste, checkbox, numupdown and screen module. And some minor changes to the other modules.

common/system/system.h

@@ -1,6 +1,9 @@
 #ifndef SYSTEM_H
 #define SYSTEM_H
 
+#include <stdbool.h>
+#include <stdint.h>
+
 /**
  * @defgroup system System
  * The System Module provides access to delay functions, leds and provides a system init function
@@ -8,9 +11,6 @@
 /*@{*/
 
 
-#include <stdbool.h>
-#include <stdint.h>
-
 /**
  * Initializes the system. Call this method at the start of your app_init() function and before using any system_* functions
  * @return true on success