Added tasks tab with placeholder for content
Added sample tasks and javascript skeleton to update the checkboxes
Added task resource.

This adds a controller and model for tasks, which is a child of projects.

New, create, and index are implemented and tested.
Implemented task list in project task tab
Fixed turbolinks breaking checkboxes
Implemented add task on bottom of task index partial
Implemented ajax update for task checkboxes
Show 'no tasks' text if there are no tasks defined for a project
Merge pull request #70 from matthew-parlette/add_tasks

Add tasks