Upgrade to SBT v0.13.0

'CrossVersion.binaryMapped' seems to work better (ie use '2.10') in
SBT v0.13.0.

Requires update of "sbt-release" plugin.

Update to release version of "lift-json" thrown in for free.
Default to doing a cross-build of Scala versions when doing a release

https://github.com/sbt/sbt-release
https://github.com/sbt/sbt-release/blob/44a85060/src/main/scala/ReleasePlugin.scala#L17
Update to latest version of Scala, because why not?