SI-6811 Remove scala.annotation.serializable

Every usage of it has been eliminated in earlier commits,
so the source file can finally be removed, too.
SI-6811 Remove usages of scala.annotation.cloneable

The source file itself will be removed later,
because the compiler seems to need it for boot-strapping.
SI-6811 Remove deprecated constructors
SI-6811 Remove primitive widenings and /:\
SI-6811 Remove scala.collection.mutable.ConcurrentMap
SI-6811 Remove the scala.util.grammar package
SI-6811 Remove parts of scala.concurrent not needed by scala.actors
SI-6811 Remove deprecated elements in scala.collection
SI-6811 Misc. removals in util, testing, io, ...
SI-6811 Remove the scala.annotation.target package
SI-6811 Remove scala.ScalaObject
SI-6811 Remove scala.xml.include.sax.Main
Merge pull request #1921 from soc/SI-6811-removals

SI-6811 Scheduled removal of deprecated items for 2.11