如何更改Play,SBT及其插件使用的Scala版本？

我正在使用Play Framework 2.1.1-RC2.我想创建将使用Scala 2.10.1的新项目.为了达到,我做了以下

>添加依赖关系“org.scala-lang”％“scala-compiler”％“2.10.1”在Build.scala
>在Build.scala中初始化变量scalaVersion为2.10.1

然后我运行命令,并得到以下输出

[test2] $about
Getting Scala 2.10.1 ...
downloading http://repo1.maven.org/maven2/org/scala-lang/scala-compiler/2.10.1/scala-compiler-2.10.1.jar ...
        [SUCCESSFUL ] org.scala-lang#scala-compiler;2.10.1!scala-compiler.jar (7401ms)
downloading http://repo1.maven.org/maven2/org/scala-lang/scala-library/2.10.1/scala-library-2.10.1.jar ...
        [SUCCESSFUL ] org.scala-lang#scala-library;2.10.1!scala-library.jar (4309ms)
downloading http://repo1.maven.org/maven2/org/scala-lang/scala-reflect/2.10.1/scala-reflect-2.10.1.jar ...
        [SUCCESSFUL ] org.scala-lang#scala-reflect;2.10.1!scala-reflect.jar (2144ms)
downloading http://repo1.maven.org/maven2/org/scala-lang/jline/2.10.1/jline-2.10.1.jar ...
        [SUCCESSFUL ] org.scala-lang#jline;2.10.1!jline.jar (201ms)
:: retrieving :: org.scala-sbt#boot-scala
        confs: [default]
        5 artifacts copied,0 already retrieved (24386kB/58ms)
[info] This is sbt 0.12.2
[info] The current project is {file:/C:/work/test_projects/test2/}test2
[info] The current project is built against Scala 2.10.1
[info] Available Plugins: play.Project,sbt.PlayProject,com.typesafe.sbteclipse.plugin.EclipsePlugin,com.typesafe.sbtidea.SbtIdeaPlugin
[info] sbt,sbt plugins,and build definitions are using Scala 2.9.2

最后一行是我关心的.它说Scala 2.9.2被使用.我该怎么改呢？它会影响什么版本将用于编译我的代码？

更新：看起来像这种改变版本的编译器不能正常工作.运行我的应用程序后,我在播放控制台中有以下警告：

[warn] Potentially incompatible versions of dependencies of {file:/C:/work/test_projects/test2/}test2:
[warn]    org.scala-lang: 2.10.1,2.10.0
[info] Compiling 5 Scala sources and 1 Java source to C:worktest_projectstest2targetscala-2.10classes...
[info] 'compiler-interface' not yet compiled for Scala 2.10.1. Compiling...
[info]   Compilation completed in 8.608 s
[warn] Potentially incompatible versions of dependencies of {file:/C:/work/test_projects/test2/}test2:
[warn]    org.scala-lang: 2.10.1,2.10.0
[info] play - Application started (Dev)
[warn] Potentially incompatible versions of dependencies of {file:/C:/work/test_projects/test2/}test2:
[warn]    org.scala-lang: 2.10.1,2.10.0