Maya Bindings : Use Py3 compatible string API

I believe PyBytes_* was available in Py2 as well

Author: andrewkaufman

src/IECoreMaya/bindings/MDagPathFromPython.cpp

@@ -49,7 +49,7 @@ struct MDagPathFromPython
 {
 	static void *convertible( PyObject *obj )
 	{
-		if( PyUnicode_Check( obj ) || PyString_Check( obj ) )
+		if( PyUnicode_Check( obj ) || PyBytes_Check( obj ) )
 		{
 			return obj;
 		}
@@ -68,12 +68,12 @@ struct MDagPathFromPython
 		if( PyUnicode_Check( obj ) )
 		{
 			PyObject *ascii = PyUnicode_AsASCIIString( obj );
-			name = PyString_AsString( ascii );
+			name = PyBytes_AsString( ascii );
 			Py_DECREF( ascii );
 		}
 		else
 		{
-			name = PyString_AsString( obj );
+			name = PyBytes_AsString( obj );
 		}
 
 		MSelectionList s;

src/IECoreMaya/bindings/MObjectFromPython.cpp

@@ -49,7 +49,7 @@ struct MObjectFromPython
 {
 	static void *convertible( PyObject *obj )
 	{
-		if( PyUnicode_Check( obj ) || PyString_Check( obj ) )
+		if( PyUnicode_Check( obj ) || PyBytes_Check( obj ) )
 		{
 			return obj;
 		}
@@ -68,12 +68,12 @@ struct MObjectFromPython
 		if( PyUnicode_Check( obj ) )
 		{
 			PyObject *ascii = PyUnicode_AsASCIIString( obj );
-			objectName = PyString_AsString( ascii );
+			objectName = PyBytes_AsString( ascii );
 			Py_DECREF( ascii );
 		}
 		else
 		{
-			objectName = PyString_AsString( obj );
+			objectName = PyBytes_AsString( obj );
 		}
 
 		MSelectionList s;

src/IECoreMaya/bindings/MPlugFromPython.cpp

@@ -49,7 +49,7 @@ struct MPlugFromPython
 {
 	static void *convertible( PyObject *obj )
 	{
-		if( PyUnicode_Check( obj ) || PyString_Check( obj ) )
+		if( PyUnicode_Check( obj ) || PyBytes_Check( obj ) )
 		{
 			return obj;
 		}
@@ -68,12 +68,12 @@ struct MPlugFromPython
 		if( PyUnicode_Check( obj ) )
 		{
 			PyObject *ascii = PyUnicode_AsASCIIString( obj );
-			plugName = PyString_AsString( ascii );
+			plugName = PyBytes_AsString( ascii );
 			Py_DECREF( ascii );
 		}
 		else
 		{
-			plugName = PyString_AsString( obj );
+			plugName = PyBytes_AsString( obj );
 		}
 
 		MSelectionList s;

src/IECoreMaya/bindings/MStringFromPython.cpp

@@ -48,7 +48,7 @@ struct MStringFromPython
 {
 	static void *convertible( PyObject *obj )
 	{
-		if( PyUnicode_Check( obj ) || PyString_Check( obj ) )
+		if( PyUnicode_Check( obj ) || PyBytes_Check( obj ) )
 		{
 			return obj;
 		}
@@ -67,12 +67,12 @@ struct MStringFromPython
 		if( PyUnicode_Check( obj ) )
 		{
 			PyObject *ascii = PyUnicode_AsASCIIString( obj );
-			new (storage) MString( PyString_AsString( ascii ) );
+			new (storage) MString( PyBytes_AsString( ascii ) );
 			Py_DECREF( ascii );
 		}
 		else
 		{
-			new (storage) MString( PyString_AsString( obj ) );
+			new (storage) MString( PyBytes_AsString( obj ) );
 		}
 
 		data->convertible = storage;