Add ZSH completion

[glittershark]

No description provided.

[scharfie]

I was able to use the bash completion script to work in my zsh (5.0.5, OS X) with the following:

autoload bashcompinit
bashcompinit
source /path/to/projectionist/completion.bash

[glittershark]

That is an excellent work around! I still definitely want to do native zsh completion at some point, but this is really helpful in the meantime.