Improve help in Play2 IDE stb eclipse command

[aldenml]

I think it's worth mentioning that when you are working with submodules (since play2 projects are based on sbt), passing the arguments skip-parents=false will (re)create all your eclipse projects (one for each submodule).

Also putting the link as "More info for the eclipse command" will help: https://github.com/playframework/Play20/blob/master/documentation/manual/detailledTopics/build/SBTSubProjects.md

The image still show the old eclipsify command.

Thanks!