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
Merge pull request #440 from dotta/transient/sbt-master-version-back-to-SNAPSHOT

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