The offender was `print -P`, where `-P` does [prompt
expansion](http://zsh.sourceforge.net/Doc/Release/Prompt-Expansion.html#Prompt-Expansion).
I took the freedom to also change a few things:
Move the `add-zsh-hook precmd` up,
add `prompt_magicmace_` prefix to all function names,
add `COLOR_` prefix to all color global variables,
and move assignment to `PROMPT` to `prompt_magicmace_setup`.
Fixes#70, Closes#81
