[3/5] imagehlp: Implement ImageAddCertificate

[Owen Rudge]

> The virtual address is not necessarily the same as the disk offset.

Actually, it seems that the security directory is one of the few places 
where a disk offset is intentionally used. Trying to compensate for the 
virtual address results in failure in this case.

I have been amending the code to make it more robust however, and shall 
submit a revised version tomorrow.

-- 
Owen Rudge
http://www.owenrudge.net/