show error if run with Xcode 4 or lower.

We're dropping support for Xcode 4.
should show build #error if Xcode is < 5.0.

We're dropping support for the Xcode 4 toolchain.
adding a Run Script to verify libs are built as Universal

... and fixing the cases for otest-query*-osx where the lib was only
built as x86_64 in debug mode.
switching xctool to use the clang-as-ios-dylib workaround.

We can now retire the iOS-Simulator-Dylib.xcconfig stuff.
remove support for running GC-enabled tests.

Xcode 5.1 will drop support for building GC-enabled binaries, so we
should drop it in Xcode, too.
fix leak in ArchiveAction
when overriding test names, override `name` and `description`.

should fix #273