已下载Typesafe Stack 2.0.2并已安装，但键入sbt会给出...
[warn] ::::::::::::::::::::::::::::::::::::::::::::::
[warn] :: UNRESOLVED DEPENDENCIES ::
[warn] ::::::::::::::::::::::::::::::::::::::::::::::
[warn] :: org.lifty#lifty;1.7.4: not found
[warn] ::::::::::::::::::::::::::::::::::::::::::::::
任何线索？