links for related generic objects implemented

Found your app useful but generic relations was missing.
Think it will be usefull for all and implemented it.

Cache used. Defauls:
getattr(settings, 'RELATIVES_CACHE_KEY', 'relatives_cache')
getattr(settings, 'RELATIVES_CACHE_TIME', int(60*60*24))

Also:
1. Template was updated and now it's more presentable.
2. Styles were moved to separate css file, placed as usually in 'static' dir.

Hope u like it :)
Tip for future: you might consider installing EditorConfig so your editor will automatically insert final newlines at the ends of your files in this project (and generally obey EditorConfig rules in projects in general).