Update setup.py & manifest & path for images displayed in gui

gui/MANIFEST.in

 include README.md
 recursive-include cadbiom_gui/gt_gui/chart_glade/ *.glade
-include cadbiom_gui/gt_gui/legend.png
+include cadbiom_gui/gt_gui/images/*

gui/cadbiom_gui/gt_gui/chart_misc_widgets.py

@@ -324,7 +324,7 @@ class LegendWindow(object):
         image = gtk.Image()
         template = pkg_resources.resource_filename(
             __name__,
-            "legend.png"
+            "images/legend.png"
         )
         image.set_from_file(template)
         image.show()

gui/cadbiom_gui/gt_gui/charter.py

@@ -379,7 +379,7 @@ class Charter(object):
         # Get resource
         template = pkg_resources.resource_filename(
             __name__,
-            image_file + '.png',
+            'images/' + image_file + '.png',
         )
         image.set_from_file(template)
         widget.set_image(image)