Updated `sbt.version` for Scala 2.10 and 2.11 profiles

The version of Sbt 0.13 (master) changed back from Beta1 to
SNAPSHOT, hence we need to update the profiles for Scala 2.10
and 2.11 to pass the right value fot `sbt.version`.

This commit basically reverts the changes in the POM made by
SHA: c4f66e5324a014d7587b4bdfaa9a47f7b3a221b5