XCode CLI Tools script: Add support for OS X 10.10

Surprisingly the "hack" works almost the same way except they've renamed the update in the last OS X.

Here's the full output from `softwareupdate -l`:

```
Software Update Tool
Copyright 2002-2012 Apple Inc.

Finding available software
Software Update found the following new or updated software:
   * Command Line Tools (OS X 10.10)-6.0
	Command Line Tools (OS X 10.10) (6.0), 108534K [recommended]
   * iTunesX-12.0
	iTunes (12.0), 160725K [recommended]
```

btw. In case you'd be curious, I actually had to install the Yosemite manually onto a fresh 10.9, because there are still some known issues with fresh 10.10 installations, so the whole setup has not been fully tested for `10.10` yet.