add init code for clickable task page (buggy)
 fix save task fail
fix the add comment error for task with specific time
 add history to task detail page
add subscribe/unscribe email feature.
 refine to only change order without duplication
add task list with group feature !
 fix  task list NilClass error when not logined
add export feature, fix bugs
make fix comment privilege to be consistent to fatfreecrm
fix the delete! to all my tasks (including assigned to me)
Merge branch 'group_tasks' into roadt_master
remove create task message in group task list page if the task list is not my tasks
fix bug that on pending page, the assigned task item are rendered.
 add multilingual(locale) files
 commit missing file for export feature
Merge branch 'group_tasks' into roadt_master
make sidebar filter valid to all users
fix typo
refine the engine loader order so that production mode and test mode works well