Feature request: calculate Authenticode hash

[tklengyel]

When examining EFI PE files, it is very useful to calculate the Authenticode hash, which is used by the UEFI firmware to record measurements into the TPM. Currently pehash does not produce this hash.

More info: https://msdn.microsoft.com/en-us/library/windows/desktop/ms680547(v=vs.85).aspx#appendix_a__calculating_authenticode_pe_image_hash