Bundle SoftwareI2C library (with edits)

libraries/Arduino_Software_I2C-master/README.md

@@ -0,0 +1,30 @@
+Arduino_SoftWareI2C  [![Build Status](https://travis-ci.com/Seeed-Studio/Arduino_Software_I2C.svg?branch=master)](https://travis-ci.com/Seeed-Studio/Arduino_Software_I2C)
+===============
+
+
+This is an Arduino software I2C Library, you can use the other pin as I2C interface, such D2, D3.
+
+But, you should know that this library can only act as Master.
+
+And, Wire.available() is not correctly supported.
+
+This library include:
+
+
+    void begin(int Sda, int Scl);                   // setup
+    uchar beginTransmission(uchar addr);            // start
+    uchar endTransmission();                        // end
+    uchar available();                              // bytes available for reading
+
+    uchar write(uchar dta);                         // write a byte
+    uchar write(uchar len, uchar *dta);             // write a array
+    uchar requestFrom(uchar addr, uchar len);       // request some data
+    uchar read();                                   // read a byte
+
+
+
+begin() is something different from <Wire.h>, you have to set pin here.
+beginTransmission() return the uchar, original not.
+available() return the length set by requestFrom().
+
+The others function is just like the hard I2C library.