1. Go binary: ../bin/fzf
2. System fzf: $(which fzf)
3. Download fzf from GitHub or create wrapper script to Ruby version (../fzf)
   when the binary for the platform is not available
4. If install script is not found or for some reason failed, try to use Ruby
   version in its expected location (../fzf)
5. If fzf is found to be a shell function, use it (type fzf)