Update OSX Support for CLI

fixes the following issues and allows to successfully clean,build,run osx platform on cli

* CB-2920 Add a ./cordova/clean project-level script for OSX
* CB-2934 Add a ./cordova/build project-level script for OSX
* CB-2946 Add a ./cordova/run project-level script for OSX
* CB-2802 add a ./bin/check_reqs script to OS X
* CB-2803 Add CLI scripts for OS X
* CB-3343 OSX - add version script