Retrieves the preview generator from GitHub

tracim/setup.py

         ]
     },
     dependency_links=[
-        "http://tg.gy/230",
+        'http://github.com/algoo/preview-generator/tarball/master#egg=preview_generator-1.0',
         ],
     zip_safe=False
 )

tracim/tracim/controllers/content.py

         file_path = content_api.get_one_revision_filepath(revision_id)
         nb_page = 0
         try:
-            nb_page = preview_manager.get_nb_page(file_path=file_path)
+            nb_page = preview_manager.get_page_nb(file_path=file_path)
         except:
             pass
         preview_urls = []