Changed git:// to https:// to allow for updates on cloned machine + Documentation

It might be me, but after I cloned a castle to one of my machines, made some changes to a file and tried to push it back to my repo, I got `You can't push to git://github.com/fenekku/dotfiles.git`. I think it's because `homeshick clone` uses `git://` to get the repo instead of `https://` and github.com doesn't seem to allow pushes via `git://`. So I changed the protocol to https. Now I didn't see any other people mentioning this issue so I might very well be missing something obvious here :) .

This not withstanding, I also updated the documentation to make the updating of one's castle files clearer: issue #30 and #31 hint at some confusion there. Maybe this makes it clearer.

I've also changed the blue s to a blue h in the help.sh. You meant to emphasize the difference between homesick and homes*h*ick right ;) ?