Added install target for libzdl
Switched to BFD (Binary File Descriptor) library from binutils distr.

Added reference counting, symbol hash lookup.
Tests added.

Currently they pass only if linked with "--allow-multiple-definition --unresolved-symbols=ignore-in-object-files -whole-archive -lc -no-whole-archive" inside spec file.

Another way to include all libc symbols is generating dummy code that forces linker to include ALL symbols from static library. By default it only includes only referenced symbols what leads to failing dlsym on some symbols.