ios improvements and new example

A number of improvements and a new ios example

- expose more module options in the ios build process
- add support for gesture based events
- add gesture reconition for cases where the native gesture
  recognizers are not used
- modify the multitouch interactor style to be based off
  the gestures
- modify the plane widget to support the pinch gesture as an example
- create a new iOS example called planeview that demonstrates
  - using multitouch gestures
  - loading data from a cloud provider
  - using a splash screen
  - using a settings page to control options
  - using a probe widget