Added Melange front page edit view where you can change title, content, feed url. Created SiteSettings and Document models and some logic for them. Added isFeedURLValid function in soc/logic/feed.py. Created some functions for handling datastore updates of different kinds of Models (soc/logic/model.py). Fixed some typos and too long lines of code. Patch by: Pawel Solyga Review by: to-be-reviewed