Remo/concrete5 — pull request #2 by mlocati (2013-08-08 10:12:41+00:00)
Title: Add events to GenerateSitemap job

Let's add two events:
- `on_sitemap_xml_addingpage`: to allow customizing the node (for instance, multilingual package may use this) if returns -1 the page gets removed.
- `on_sitemap_xml_ready`: called just before saving the sitemap, so packages can add/remove their nodes)