Renamed static.py to staticfile.py

Python 3 supports 'namespace packages', and thus can see a directory
without __init__.py as something importable. This caused a name conflict,
since there were both the file static.py and the dir static.

pillar/__init__.py

@@ -280,7 +280,7 @@ class PillarServer(Eve):
                                                ext.static_path)
 
     def register_static_file_endpoint(self, url_prefix, endpoint_name, static_folder):
-        from pillar.web.static import PillarStaticFile
+        from pillar.web.staticfile import PillarStaticFile
 
         view_func = PillarStaticFile.as_view(endpoint_name, static_folder=static_folder)
         self.add_url_rule('%s/<path:filename>' % url_prefix, view_func=view_func)