Ripple expects to find Cordova globally installed

Ripple calls cordova prepare expecting to find cordova globally installed. And worse, in case it doesn't it fails silently. The offending line:

exec('cordova prepare ' + req.staticPlatform, function () { ...

I have a fix for this where we fallback to exec only if a call to require.resolve('cordova') fails. In any other case, we'll use cordova's prepare module for the task. See GitHub for the related pull request: https://github.com/apache/incubator-ripple/pull/24