Wire up the front-end to a REST service

Edit the api_base_url in index.html.

Endpoints required:
	- GET    /tasks                     - get all tasks (currently not used)
	- GET    /tasks/{id}                - get specific task (currently not used)
	- GET    /tasks/for_date/2014-10-25 - get all tasks for the given date
	- POST   /tasks                     - Create a new task
	- PUT    /tasks                     - Update (replace) an existing task
	- DELETE /tasks/{id}                - Delete a task

A task has:
	- title     - string
	- text      - string
	- priority  - integer in [0, 1, 2, 3]
	- completed - boolean (should default to false)
	- date      - datetime - the date it is for