The key here is not using MENU_COMPLETE which autoselects the first
entry, but using AUTO_MENU which displays the menu but autoselects
on successive tab hit.

Also, do not use zstyle menu yes because that somehow overrides
the setopts.

Only using the contents of .ssh/known_hosts when the file exists for ssh/scp auto-completion. Closes issue #20

Moving all zsh config options into a lib/ subdirectory to make way for some upcoming changes to directory structure and configuration options