CDK-451: View isReady / signalReady

This PR builds on https://github.com/kite-sdk/kite/pull/98 and https://github.com/kite-sdk/kite/pull/99 adding support for isReady / signalReady on Views.
Output committers don't work properly in Hadoop 1 (at least in the local job runner). See

https://github.com/kite-sdk/kite/blob/master/kite-data/kite-data-mapreduce/src/main/java/org/kitesdk/data/mapreduce/DatasetKeyOutputFormat.java#L304

So +1 to not having a ready signal in Hadoop 1 and excluding from the test.