Set BreakBeforeBraces to Attach

Even though I've seen code from Apple breaking a line before opening braces after a method declaration (just like in `BreakBeforeBraces: Linux`) I'd say that setting it to `Attach` is a better option considering that all the code templates on Xcode 6 and the [WatchKit Lister App] (https://developer.apple.com/library/prerelease/ios/samplecode/Lister/Introduction/Intro.html) do not break a line before braces.