Update defaults.

 - Updated from http://mths.be/osx

 - Modified for America/Los_Angeles, US locale.

 - Moderately modified from @mathiasbynens original to
   match my own preferences. Things like Disk Image verification
   quarantines, Time Machine, and a few other things remain enabled.
   Many other small changes exist.
Merge branch 'master' of https://github.com/reid/dotfiles