Use LIEF library to parse ELF and PE symbols

[rdbo]

LIEF is a C++ library that can parse multiple types of binaries and among other features, dump their debug symbols.
As mentioned in the issue #26, libmem has to become more modular. Maintaining all of these features by myself is not a good idea, especially since there are libraries out there that will do a better job.
I have been trying to use LIEF on libmem, but because it is a C++ library, I've had a few problems integrating it. Nonetheless, I still think it's important to use it.

[rdbo]

LIEF Project: https://github.com/lief-project/LIEF/

[rdbo]

Fixed: ae07c0f and cc86bc6