demonstration of Xcode 5.1 + calabash cannot launch iOS simulator

***DEMO DEMO DEMO - DO NOT MERGE***

## motivation

Demonstrates that calabash cannot launch the iOS simulator.

#### To reproduce

* Xcode 5.1
* MacOS 10.9.2
* 0.9.168.pre4

1. `$ git clone git@github.com:calabash/calabash-ios-example.git`
2. `$ git co -t origin/demo/xcode51-cannot-launch-iOS6-sim`
3. get the latest 0.9.168.pre5 calabash-ios gem
4. use bundler + calabash-ios-example/Gemfile to get you gem environment into a good shape
     - follow the instructions in the Gemfile to use the local calabash-ios gem
         * `$ bundle config.local.calabash-cucumber ~/path/to/your/local/calabash-ios/repo`
         * update the Gemfile case statement with your Unix username and github repo info (follow the examples)
5. `$ bundle update && bundle install`
6. `$ DEVICE_TARGET="iPhone - Simulator - iOS 6.1" DEBUG=1 be cucumber`

###### expected

To be able to run cucumber against the iOS 6.1 simulator.

###### found

The simulator version changes correctly.

If app launches, no Scenarios are run and the run_log.out contains:

```
sim[94620:303] /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/usr/bin/sim: 
    Dead bootstrap subset.
Fail: Could not start script, target application is not frontmost
```

###### notes

reproducible on these `DEVICE_TARGETS`

```
iPhone - Simulator - iOS 6.1
iPhone Retina (3.5-inch) - Simulator - iOS 6.1
iPhone Retina (4-inch) - Simulator - iOS 6.1
iPad - Simulator - iOS 6.1
iPad Retina - Simulator - iOS 6.1
```

did not test these (invalid?) targets:

```
# these arch/iOS versions are invalid - why are they listed?
iPad Retina (64-bit) - Simulator - iOS 6.1
iPhone Retina (4-inch 64-bit) - Simulator - iOS 6.1
```

Tested iOS 7 simulators on briar-ios-example (non-trivial example).