add utility method to determine if we are running on a simulator.
add utility method to determine if we are running on a simulator.

misfitdavidl/tuneup_js,MYOB-Technology/tuneup_js,Northern01/tuneup_js,songxiang321/ios-monkey,misfitdavidl/tuneup_js,Northern01/tuneup_js,MYOB-Technology/tuneup_js,alexvollmer/tuneup_js,songxiang321/ios-monkey,alexvollmer/tuneup_js