Update bin/osxdefaults

Update bin/osxdefaults to install the Solarized palette for Apple Color
Picker and profiles for OS X Terminal.
Add lib/setup

Move `link` and `mirrorfiles` functions from bin/dotfiles to lib/setup.
Update lib/utils functions

Update logging functions. Add `e_question` and `e_process` functions.
Update bin/dotfiles to set Git credentials

Add `set_git_credentials` function to lib/setup.