mraa.i: add idef for SWIGPYTHON on doc interface files

This fixes compilation of node.js module with doxygen

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

src/mraa.i

@@ -5,6 +5,8 @@
 %include exception.i
 
 #ifdef DOXYGEN
+  //and doesn't seem to work correctly in SWIG's preprocessor
+  #ifdef SWIGPYTHON
         %include common_hpp_doc.i
         %include gpio_class_doc.i
         %include i2c_class_doc.i
@@ -12,6 +14,7 @@
         %include aio_class_doc.i
         %include spi_class_doc.i
         %include uart_class_doc.i
+    #endif
 #endif
 
 %{