demonstration of Xcode 5.1 + calabash cannot launch iOS 6 simulator

*** DEMO DEMO DEMO - DO NOT MERGE ***

## motivation

Demonstrates that calabash cannot launch the iOS 6.1 simulator.

#### To reproduce

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.pre4 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
```

Occasionally, I see this MacOS dialog:

[ios-sim crash](demo/2014-03-18_11-57-57.png)