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+ Now sitetree uses native Django cache framework (see 16).
+ Added "in_current_branch" item attribute (see 14, 18), and "current_branch" css class.
* South migrations are now shipped within application package (see 19).
* Current menu item now preserves "a" tag, and marked with "current_item" css class.
* Request object passing forced to "menu" method (fixes 15 ).
* Fixed "save & continue" wrong redirect on item's add page.
* Minor fixes.