NativeScript 2.0 warning needs to reference how to install updated cocoapods when xcode 7.3 supported version of pods is released

[stephenfeather]

If the user has a lower version of cocoapods installed, the installer suggest they install xcproj to work around the problems listed in #1639.

The better outcome would be for the user to update all their tooling if possible. The suggestion regarding xcproj, as i see it is a backwards compatibility stub, while showing the instructions to update their cocoapods is future looking.

Current warning and suggestion:

You are using CocoaPods version 0.39.0 which does not support Xcode 7.3 yet.
In order for the NativeScript CLI to be able to work correctly with this setup you need to install 
xcproj command line tool and add it to your PATH. Xcproj can be installed with homebrew by running 
$ brew install xcproj from the terminal

Suggested warning:

You are using CocoaPods version 0.39.0 which does not support Xcode 7.3 yet.

You can update your cocoapods by running $sudo gem install cocoapods --pre from a terminal.

In order for the NativeScript CLI to be able to work correctly with your current setup you would need to install 
xcproj command line tool and add it to your PATH. Xcproj can be installed with homebrew by running 
$ brew install xcproj from the terminal

[enchev]

Fixed with #1803