change lodepng to be an object lib

we are treating it as a built in dependency, the best way to do this is to compile it as an object lib so client code doesn't have to explicitly link to it

Start by locating how lodepng is currently compiled and linked, then trace the client build entry point that requires an explicit lodepng link. Confirm how the project represents an object library and identify the affected build configuration. Done means client code no longer needs to link lodepng explicitly while still building and using it successfully.

Written by the indexing model from the issue text.