code: public static String getDefaultCompilerId( String sbtVersion, String playVersion )
      {
          String result = null;
          if ( sbtVersion != null && !sbtVersion.isEmpty() )
          {
              if ( sbtVersion.equals( "0.13" ) || sbtVersion.startsWith( "0.13." ) )
              {
                  result = "sbt013";
              }
              else if ( sbtVersion.equals( "0.12" ) || sbtVersion.startsWith( "0.12." ) )
              {
                  result = "sbt012";
              }
          }
          if ( result == null )
          {
              if ( playVersion != null && !playVersion.isEmpty() )
              {
                  if ( playVersion.startsWith( "2.1." ) || playVersion.startsWith( "2.1-" ) )
                  {
                      result = "sbt012";
                  }
              }
          }
          if ( result == null )
          {
              result = "sbt013"; // use latest version
          }
          return result;
      }
docs: Returns compiler ID compatible with given SBT or Play&#33; Framework version.
  
  @param sbtVersion SBT version
  @param playVersion Play&#33; Framework version
  
  @return compiler ID