Configure

This patch includes some variables that can be set in your zshrc to move around antigen-hs files, so you can keep them where you want.  This is useful, as people might like to keep the antigen-hs repository in a place like ~/dotfiles/antigen-hs as a submodule rather than manually cloning it to ~/.zsh/antigen-hs.  They might also like the output files in something that already exists on their system, like ~/.cache, to avoid cluttering their home directory with another ~/.something.

Let me know what you think.