DOC: Update installation instructions in README.md
Hello, thanks for this great package. As I saw several users struggling with the installation, I suggest some modifications for the README installation section:
- separating more clearly the section "Precompiled binaries" from "Compilation from source".
- adding missing requirements. I made the supposition that the section "Requirements" was only needed for source compilation, if not it would be nice to have a requirements section adapted to each of the installation section (binaries, from source).
- giving an example of requirements installation makes it easier to understand how to deal with it. As an example, following the README, I spent quite a while looking for the SuperBuild archive of dependencies on the web without finding any, before having a look into the SuperBuild code and finding out it was automatically downloaded.
Thus, here is a merge request with modifications of the installation section of the main README according to the experience I had. Hope it can help. Florian