Fix vim highlighting for code folds
Add vim command for changing the CtrlP working dir
Use colour in the vim Grunt command output
Load shell aliases and functions from zshenv

Previously I was loading my shell aliases and functions from my zshrc
file which gets loaded for all interactive zsh shells. However, I
want to be able to use these aliases and functions from non
interactive shells too - for example, when making shell calls from
vim like :!tl. Zsh always loads zshenv so move the definition of the
aliases and functions into this file.