Fileinfo: VisualBasic header parsing + P-Code detection

[PeterMatula]

Visual Basic can be compiled into binary or P-Code - bytecode for VB virtual machines. Add VBHeader parsing and dumping to fileinfo. Description.

How to do it:

• When Visual Basic is detected, look at EP where should be push offset 0x????????. VBHeader should be at this offset. Some of its records are pointers to other structures (e.g. ProjectInfo).
• Add detection of P-Code (aNativeCode == 0), tag the input as bytecode, warn users that decompiling this is not a good idea.

This might help: https://github.com/SekoiaLab/pe-tools

Also some pictures from IDA where these structures were defined and used:

[s3rvac]

I am closing the issue as it has been implemented in #440.