Update Play version on skeletons
Update Play version on sbt plugins
Update Play version on API docs
Update Play version on documentation
Update documentation/manual/javaGuide/main/http/JavaActionsComposition.md
Cleanup and more details.

- More details at the beginning on how to upgrade from Play 2.0.
- General cleanup
Update documentation/manual/detailledTopics/production/Deploying-CloudFoundry.md
Merge pull request #635 from benmccann/patch-4

Update documentation/manual/detailledTopics/production/Deploying-CloudFo...
Merge pull request #634 from jamesward/fix/migration-guide

Cleanup and more details.
Merge pull request #628 from benmccann/patch-3

Update documentation/manual/javaGuide/main/http/JavaActionsComposition.md
Merge pull request #627 from ndeverge/20to21

Update versions in artefacts from 2.0 to 2.1