Update git author setup to after mirrorfiles

I think I finally figured this one out.  Everytime the user runs the
mirrorfiles function they'll wipe out any git config user information,
so put it right after that section so on first install they'll have to
hit this section, and any subsequent times after they wipe it out
they'll be prompted to put it back in.

Issue: #21
Delete unnecessary print function; update typo

There is no need to print out the helper files are being source,
especially when you run `dotfiles` after install, its the first thing
printed and isn't necessary.  Also fix a reference to a incorrect
function name in a comment (setup_osx vs osxdefaults).

Issue: #18
Create fresh install flag to setup apps

On a fresh install, I want to open up the essential apps (Alfred &
Dropbox) so that I can set them up for use.

Issue: #19