Bundle SoftwareI2C library (with edits)

libraries/Arduino_Software_I2C-master/examples/SoftwareI2C_Scan/SoftwareI2C_Scan.ino

@@ -0,0 +1,26 @@
+// i2c scan
+#include "SoftwareI2C.h"
+
+SoftwareI2C softwarei2c;
+
+void setup() {
+    Serial.begin(115200);
+    softwarei2c.begin(3, 2);       // sda, scl
+    Serial.println("begin to scan...");
+}
+
+void loop() {
+    for (unsigned char i = 1; i <= 127; i++) {
+        if (softwarei2c.beginTransmission(i)) {
+            Serial.print("0x");
+            Serial.println(i, HEX);
+
+            while (1);
+        }
+        softwarei2c.endTransmission();
+    }
+
+    Serial.println("find nothing");
+    while (1);
+
+}