Compilation with analysis independent of Scala version of sbt.

Basic test for this.

launch/interface/src/main/java/xsbti/ScalaProvider.java

@@ -0,0 +1,9 @@
+package xsbti;
+
+import java.io.File;
+
+public interface ScalaProvider
+{
+	public ClassLoader getScalaLoader(String scalaVersion);
+	public File getScalaHome(String scalaVersion);
+}