Add a new link unit to the right column that loads in an iframe

[khaled]

Add a the capability to add a new linking unit to the right column that loads an iFrame. The frame should be 300x125 pixs in size and the source should be settable from within the back-office.

Additionally, to allow 3rd party cookies in IE, add the following P3P code to the header of our pages.

header('P3P:CP="IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT"');

A sample of the source link for one of these iFrame link sharing units can be found here:

http://www.livescience.com/latest/

Recall that we may want to have more than one of these appear on the page, so please design accordingly.

[maryann]

Done and committed to trunk.