Login Page

Initial version of the login page.
Note: I'm including a pairing_page.php to show how to get the session
variable.
Revert "Login Page"

This reverts commit deafcb533c20b29301ec64edf281f0d4313e0e11.
Login Page

Initial version of the log in page.
Note: I included a pairing_page.php to show how to access the session
variable the contains the user_id logged in.