Fixes Bazaar support for zsh

This fixes issue #301.

Local arrays are not directly supported in zsh, so `local tuple` is declared and initialized on two separate lines.

Unlike bash, words separated by a space are not split into arrays in zsh. If zsh is the shell, the function local options are set to support `sh_word_split`, which supports bash-like splitting. By using function local options the user's setting for sh_word_split is unaffected.