Redirect static methods of java.lang.String to RuntimeString.

This avoids to define the companion object of java.lang.String
in Scala, which is asking for trouble.
Do not use flag 0 with format specifier %s because it is not valid.
Do not rely on the extractor for AnnotatedType.

Because its signatured changed in 2.11.0-RC1.
Merge pull request #333 from sjrd/static-methods-of-string

Some cleanups, towards support of 2.11.0-RC1