Added Notices model load and function calls

Added load->model for Notices_model. Added function calls to notices
methods for data retrieval.
Changed Calendar link

Changed calendar page link to call to a calendar controller.
Changed from static html to for each

Changed the base html for the notices accordions to php foreach loops
to echo out content from data array.
Created Notices Model

Created Notices_model to fetch notices information from database. Each
function fetches data based on the category for each notice and based
on student id which is passed in.