Add Node.js SDK

Added Node.js SDK for PredictionIO by Asaf Yishai to Community-powered
Projects
Update movielens.md
Add C#/.NET SDK

Added C#/.NET SDK for PredictionIO by Themos Piperakis to
Community-powered Projects
Add Vagrant Installation for PredictionIO

Added Vagrant Installation for PredictionIO by Raphael Mäder to
Community-powered Projects

Also added links from main Installation documentation
adding warning message for 0.8.1 CLI change
remove CLI warning msg
Merge branch 'livedoc' into develop

Conflicts:
	docs/manual/tutorials/engines/itemrec/movielens.md