GH-19: Respect the HIST_FIND_NO_DUPS option.
GH-19: Respect the HIST_FIND_NO_DUPS option.

This is the best way I've found to remove duplicate entries while
keeping the most recent occurence, but I'm not a ZSH expert. There may
be a more efficient way.

joshuarubin/dotfiles,joshuarubin/dotfiles,joshuarubin/dotfiles,joshuarubin/dotfiles