Switch to non-deprecated methods in `JavaConversions`.

The old methods in `JavaConversions` were deprecated in Scala 2.9
and finally removed in 2.11.0-M1.

This change migrates to new methods in `JavaConversions` that serve
as replacements for deprecated methods.

This fixes a build of ScalaSTM against Scala 2.11.0-M1.
Merge pull request #36 from gkossakowski/scala-2.11.0-M1-fixes

Switch to non-deprecated methods in `JavaConversions`.