Fix LazyScalaJSScope.getDefaultValue().
Implement more methods of java.lang Number types.
Fix console output through print/println.

Before, print() would print a newline, and println()
with an empty string would not print anything.

Now this is fixed by bufferint partial lines, and
emitting a console.log/console.error call only for
completed lines.
Add scala.runtime.Statics in library-aux.
Fix bug in ScalaJS.dynamicIsAssignableFrom().
Overload scala.App not to access scala.Properties.

scala.Properties is not supported because
java.util.Properties is not supported. Now a lot of
tests in partest use App, so we need App to work.
Fix error reporting in RhinoBasedRun.
Add scala.math.ScalaNumber in library-aux.
Fix some unrecognized shapes of trees for loops.