XCode6 support with releasable framework, Remove support for XCode5

This adds proper XCode6 support. There is a new configuration Release-Combined which is built from build.sh (and can be built from XCode). This configuration builds and tests a fat framework and installs it at build/ios/Realm.framework

All examples have been updated to work with the new framework.

@tgoyne @jpsim 
XCode->Xcode

> Xcode6 is now supported from the main Xcode project Realm.xcodeproj. Xcode5 is no...