Changes for 10.9 support

- Detect a 10.9 ESD and make the new ISO out of BaseSystem.dmg by converting to RW, growing it and installing Extras there
  - It's very possible there is a more efficient method to do this
- Xcode CLI tools script uses install-on-demand trigger file and a bunch of shell pipes to install from SUS
New September Xcode CLI tools for Mountain Lion, compat. with Xcode 5.
Support for 'autologin_vagrant_user' user var in Packer template.
Update README with autologin_vagrant_user Packer var.
Add 10.9 BOM list for building on 10.7. Thanks to Rich Trouton for finding and adding this.
Support for building 10.9.
Add October Xcode CLI tools for Mountain Lion.
Formatting
Bump LastSeenCloudProductVersion to 10.9
Merge branch 'master' of github.com:wbs75/osx-vm-templates