i2c device scan improved

include/i2c.h

@@ -2,6 +2,7 @@
 #define _I2C_H
 
 #include <Arduino.h>
+#include <BitBang_I2C.h>
 
 #define SSD1306_PRIMARY_ADDRESS (0x3D)
 #define SSD1306_SECONDARY_ADDRESS (0x3C)
@@ -22,7 +23,7 @@
 
 void i2c_init(void);
 void i2c_deinit(void);
-int i2c_scan(void);
+void i2c_scan(void);
 uint8_t i2c_readBytes(uint8_t addr, uint8_t reg, uint8_t *data, uint8_t len);
 uint8_t i2c_writeBytes(uint8_t addr, uint8_t reg, uint8_t *data, uint8_t len);