technical debt: swap out of outputStream_ in dotnetpelib

[LADSoft]

I needed type information in string format but the only function that created it streamed it directly to an fstream. Rather than rewrite the library I changed the fstream to an iostream and replaced the fstream with a strstream for purposes of the functions that needed the data (AdornGenerics, two instances).

At some future point the library needs to be refactored to make the strings directly available so such shenanigans can be avoided.