Include headers lib & csrf hidden form field

To help protect against CSRF and clickjacking
Also include hidden form field containing this for postback
top.ICEcoder.csrf also set
This is now set, in headers.php
headers.php included and csrf POST and GET added
headers.php included and csrf POST added
Add csrf to end of all querystrings
Add CSRF and clickjacking protection

This header file included in all PHP files as first item.
CSRF checks happen on GET or POST instances
Security related headers also added to prevent clickjacking