Form repository into library + executable

[eyalroz]

c++filt is great, but - it is also useful to be able to demangle in code. Since the functionality is already here, why not rearrange this project so that one of the targets is a (C++ I guess) library for demangling, and the executable uses it?

[nico]

That's already kinda the setup -- the main binary is all of 187 lines. What concretely would you change?

[eyalroz]

I would:

1. Add a(n aptly-named) library target in the CMakeLists.txt
2. Have the executable target depend on the library target
3. (Add cmake --install support for the library ; this takes some CMake voodoo)
4. Potentially, streamline the interface between the executable and the library so that the latter is easy to use and difficult to abuse)
5. Specify and document the library's API clearly, e.g. in the README.md file.