Start parsing EmfPlusPen, EmfPlusBrush, and EmfPlusDrawlines

[willibrandon]

This is in regards to https://github.com/dotnet/winforms/issues/4341

I've started enumerating and parsing the GDI+ records using the EMF+ specification and would greatly appreciate your feedback when you have a moment. Specifically I'm looking for some feedback on how I'm walking the byte pointer and casting to the structures, and whether or not there is a better way to do this. I haven't used pointers in this fashion before and feel like there is room for improvement here.

In the meantime, I'll start looking at enumerating and parsing the same data via the equivalent callback.

[RussKie]

Hey @willibrandon hope you've been well. Checking if you had any more progress with this.

[JeremyKuhne]

@willibrandon So sorry I missed this. I was on an extended vacation. 🙏