Rewrite logging system and sync state with clients

src/common.h

@@ -5,10 +5,16 @@
 #define UNUSED(s) (void)(s)
 
 #include <stdlib.h>
+#include <stdarg.h>
 #include <stdbool.h>
+
 #include <util/delay.h>
 #define Sleep(ms) _delay_ms(ms)
 
+void Info(const char *fmt, ...);
+void Error(const char *fmt, ...);
+void SetStateFlag(bool is_running);
+
 void Enable(void);
 void Disable(void);
 void SetTemp(long val);