Rich header parsing

[cubiclesoft]

In before anyone decides to open a support request for DOS stub Rich header parsing.

https://www.ntcore.com/files/richsign.htm

Aware of its existence as the WinPEFile class contains a sanitized DOS stub. More likely to implement a parser for it before .NET CLR header parsing since several tools (e.g. PPEE, CFF) make a point of parsing it.