Python stuff: fix an issue to build pcbnew_wrap.cxx (at least on msys2)

- Reorder two include in pcbnew.i
- rename PLUGIN to PCB_IO (missing rename) in footprint.i

pcbnew/python/swig/footprint.i

@@ -101,7 +101,8 @@
     %}
 }
 
-%extend PLUGIN
+
+%extend PCB_IO
 {
     // This version of FootprintEnumerate is for Python scripts, because the c++
     // version of FootprintEnumerate is not easy to handle in these Python scripts

pcbnew/python/swig/pcbnew.i

@@ -76,6 +76,8 @@ class BASE_SET {};
 #include <exporters/gendrill_Excellon_writer.h>
 #include <exporters/gendrill_gerber_writer.h>
 #include <exporters/gerber_jobfile_writer.h>
+#include <pcb_io/pcb_io_mgr.h>
+#include <pcb_io/pcb_io.h>
 
 BOARD *GetBoard(); /* get current editor board */
 wxArrayString GetFootprintLibraries();
@@ -84,16 +86,10 @@ wxArrayString GetFootprints(const wxString& aNickName);
 
 
 %include <pcb_io/pcb_io_mgr.h>
-%{
-#include <pcb_io/pcb_io_mgr.h>
-%}
 
 // ignore RELEASER as nested classes are still unsupported by swig
 %ignore IO_MGR::RELEASER;
 %include <pcb_io/pcb_io.h>
-%{
-#include <pcb_io/pcb_io.h>
-%}
 
 
 /*