Add some semblance of a build system

[DanielG]

Hi Vít,

Not having even so much as a simple Makefile is a disservice to packagers. Every packager for every distribution needs to figure out where to copy the executable, config files and (patch pending) manpages. This is a waste of effort and a Makefile solves this.

--Daniel

[DanielG]

FYI: I'll be following this up with a patch enabling a whole slew of warning/hardening flags.

[vitlabuda]

Hi, I have decided to use CMake for this project, so that there is something "proper" and "more pretty" than just a Makefile, which might possibly become hard to maintain. In recent commits, CMakeLists.txt has been added and relevant documentation (build instructions) have been updated accordingly. -- Vít