Set scalatest as testCompile dependency

Gradle now generates correct eclipse dependencies
@benjchristensen do you know why use `provide` here? Looks most of other projects also use `provided`. I suppose `testCompile` may be better for these test libraries. I changed `provided` to `testCompile` in rxjava-scala. Looks it works.

```groovy
dependencies {
    compile 'org.scala-lang:scala-library:2.10.+'

    compile project(':rxjava-core')
    
    testCompile 'junit:junit-dep:4.10'
    testCompile 'org.mockito:mockito-core:1.8.5'
    testCompile 'org.scalatest:scalatest_2.10:1.9.1'
}

tasks.compileScala {  
    classpath = classpath + (configurations.compile + configurations.provided)
}

tasks.compileExamplesScala {  
    classpath = classpath + files(compileScala.destinationDir) + (configurations.compile + configurations.testCompile)
}
```