fixed scheduler.c retvals

src/libsrc/scheduler.c

 #include "scheduler.h"
 
 int schedulerInit() {
+    return 0;
 } // add the IDLE task with lowest priority and first USER task maybe
 
 int pushToScheduler (KernelStruct* Colonel, TD* Task) {
-
+    return 0;
 }
 
 TD* getNextTaskScheduler (KernelStruct* Colonel) {
-    
+    return NULL;
 }