Adafruit Wire library already defines TinyWireM as Wire

So, this was a little tricky.  For Adafruit Trinket and Gemma, you want
to remove the definition of Wire as TinyWireM.  If you don’t other uses
of Wire in a sketch get messed up.
But, the Arduino Gemma doesn’t use the Adafruit Wire library.  So
Arduino Gemma compiles would fail.  I made ARDUINO_AVR_GEMMA a special
case.
Version 1.0.3

Adafruit_MCP23017.cpp

@@ -11,13 +11,6 @@
  BSD license, all text above must be included in any redistribution
  ****************************************************/
 
-#ifdef __AVR_ATtiny85__
-  #define Wire TinyWireM      //TinyWireM is now part of Adafruit Wire library
-#else
-  #include <Wire.h>
-#endif
-
-
 #ifdef __AVR
   #include <avr/pgmspace.h>
 #elif defined(ESP8266)

Adafruit_MCP23017.h

@@ -15,11 +15,18 @@
 #define _Adafruit_MCP23017_H_
 
 // Don't forget the Wire library
-//#ifdef __AVR_ATtiny85__           //TinyWireM is now part of
-//#include <TinyWireM.h>            //   Adafruit version of Wire Library
-//#else
-#include <Wire.h>
-//#endif
+#ifndef ARDUINO_AVR_GEMMA
+                                    //TinyWireM is now part of
+                                    //   Adafruit version of Wire Library, so this
+                                    // will work with Adafruit ATtiny85's
+                                    //But Arduino Gemma doesn't use that library
+                                    // We do NOT want to include Wire if it's an arduino Gemma
+  #include <Wire.h>
+#else
+  #include <TinyWireM.h>
+  #define Wire TinyWireM
+#endif
+
 
 class Adafruit_MCP23017 {
 public:

library.properties

@@ -1,5 +1,5 @@
 name=Adafruit MCP23017 Arduino Library
-version=1.0.2
+version=1.0.3
 author=Adafruit
 maintainer=Adafruit <info@adafruit.com>
 sentence=Library for the MCP23017 I2C Port Expander