SI-6979 Small optimization in lub

If a member of `lubBase` is final, it cannot be
refined in the types we're lubbing.
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
Disable MIMA in master.

Binary compatibility checks do not make sense in master because
there's no base point against which we should check.
Merge pull request #1926 from gkossakowski/disable-mima-in-master

Disable MIMA in master.
Merge pull request #1908 from retronym/ticket/6979

SI-6979 Small optimization in lub
SI-6811 Remove scala.xml.include.sax.Main
SI-6811 Move scala.util.{automata,regexp} ...
... to scala.xml.dtd.impl and make it private[dtd]
Merge pull request #1921 from soc/SI-6811-removals

SI-6811 Scheduled removal of deprecated items for 2.11
Merge pull request #1939 from soc/SI-6811-moves

SI-6811 Move scala.util.{automata,regexp} ...