Upgrade to Scala 2.11.0-M4.

And all the changes need to adapt to the new internal API
of the compiler, and other small things.
Update RefTypes.scala for Scala 2.11.
Have Partest test 'pos' and 'neg' tests of Scala.
Have Partest test 'run' tests of Scala.
Add support for blacklisting of tests.
WIP for a list of blacklisted tests.
More blacklisting of tests.