First round of common osx_defaults

@wfarr, this is getting started on that thing I talked to you about with OSX defaults.  These are super easy to use in a person manifest, for example:

``` puppet
class people::tekkub {
  include osx::finder::empty_trash_securely
  include osx::finder::show_all_on_desktop
  include osx::finder::unhide_library
  include osx::global::expand_save_dialog
  include osx::global::expand_print_dialog
  include osx::global::disable_key_press_and_hold
  include osx::global::enable_keyboard_control_access
}
```