implement task status change action

on clicking the close link beside the task will make an ajax
request to change the status of task and then task is removed
from UI
customize view for our app

- remove the title and subtitle
- add menu items `View Tasks` and `Add Task`
- add link to page displaying update task form
fix typo in db.task.attachment

database migration due to this change
update task functionality and file upload using jquery fileupload