Clarified creation of code examples

Changed the first option of example selection to "New" to clarify that a
new code example is created if none is selected.
Added some security to course and section forms
Alertbox update!
Alertbox css update........
Fixed security when adding new sections

Courseid now available as a session
Added user menu

Added a user menu when users are clicking their username next to
login/logut button.
Also added a cancel button to newpassword.php.