fix #284
add Composable#merge to connect N composable to the current pipeline
explicit consume name from consume(Composable) to connectValues(Composable)  : values forwarded; to be inline with connect(Composable) : error and values forwarded.
Add a promise.mapMany test
Promote consumeFlush to Pipeline
Fix promise flush cascading
Remove Flushable generic type constraint
Merge pull request #291 from reactor/enhancement-284-merge-and-composable-fixes

fix #284