Bump versions after release of Scala 2.11.0-RC4

Based on:

   https://scala-webapps.epfl.ch/jenkins/view/scala-release-2.11.x/job/scala-release-2.11.x/52/artifact/scala/versions.properties

With a manual edit of the new property, scala.full.version, which
was not written out by `ant -Dupdate.versions`. That has since
been remedied.
Bump Akka version to 2.3.2

Quoth @rkuhn:

> seeing that you are cutting a Scala release, we’ll need to
> decide on which Akka version to bundle with it. 2.3.0 has
> some remoting bugs which we’d like to leave behind

Given the difficult of overriding the bundled Akka version
from the Scala script runner (SI-8472), we've deemed it
worthwhile to bump the Akka version before releasing 2.11.0.
Merge pull request #3676 from retronym/release/bump-versions-2.11.0-RC4

Bump versions after release of Scala 2.11.0-RC4
WIP: trying to apply the Literal-based singleton types commit by @paulp to the master.
Fix non-working things.
Update check file.
Problems with null.
Update the check file.
This is needed for the tests to pass.
Added a macro to materialize an inhabitant for the singleton type.
Added a test with the Ranged class mentioned by @non.
Add inhabitant to the bincompat whitelist.
Marked potentiall places in code where constant type folding and singleton type inlining might occur.
Inlining functions with singleton result type.
More involved example with Ranged.
Needed for the tests to pass after adding the SingleInhabitant
Checking for declared singleton type. Tests seem to pass, but the issue is still there.
Forward bincompat.
Another problem.
Check that parser allows unicode identifiers in the type position.