Changed clock name to lowercase

usart/main.cpp

@@ -5,7 +5,7 @@
 */
 
 #include <stdio.h>
-#include "Clock.h"
+#include "clock.h"
 #include "usart.h"
 
 int main()

usart/usart.h

@@ -12,7 +12,7 @@
 #include <stdlib.h>
 #include <stdint.h>
 #include <ctype.h>
-#include "Clock.h"
+#include "clock.h"
 #include "string/string.h"
 #include "vector/vector.h"