Added home page button styles and linked buttons

Readded the styles for the buttons in the index.html file into
master.css. These are noted in the style sheet becuase of their
uniqueness in structure to the index page from the rest of the site.
These buttons where then linked to direct to the appropreate pages.
This requied minor changes to the loginInterface.html file. Also, minor
adjestments are made to the links in the loginInterface.html file for
usuallbility. These links now direct the user to sign up or cancel.