Arpegio

BREAKING CHANGES: Page and Post models changed the field modified_date to modification_date

Blog
- PostList view uses the Post model

Core
- Added a "more" templatetag.
- New models: ContentMixin and Timestampable.

Sticky field in Post

Fix problem with templates and the new apps labels.

Fix: Problem with database due apps labels.

Added templates for the apps.

This release fix a labels problem when using it in a project with apps with the same name.