Fix warning ISO C++11 does not allow conversion from string literal to

'char *

src/core/timebars.h

@@ -1,6 +1,6 @@
 #pragma once
 
 void tbInit();
-void tbStartTimer(int32, char*);
-void tbEndTimer(char*);
+void tbStartTimer(int32, const char*);
+void tbEndTimer(const char*);
 void tbDisplay();