Add pps extension to IGNORED_EXTENSIONS

	modified:   scrapy/linkextractors/__init__.py

Author: djunzu

scrapy/linkextractors/__init__.py

@@ -30,7 +30,8 @@
     'm4a',
 
     # office suites
-    'xls', 'xlsx', 'ppt', 'pptx', 'doc', 'docx', 'odt', 'ods', 'odg', 'odp',
+    'xls', 'xlsx', 'ppt', 'pptx', 'pps', 'doc', 'docx', 'odt', 'ods', 'odg',
+    'odp',
 
     # other
     'css', 'pdf', 'exe', 'bin', 'rss', 'zip', 'rar',