Upgrade the Scala ecosystem of the bootcompiler.

- sbt 0.13.6
- Scala 2.11.2
- scopt 3.2.0

Fixes #221, because Scala 2.11 should be able to read JDK8 stuff.
Merge pull request #222 from sjrd/upgrade-scala-stuff

Upgrade the Scala ecosystem of the bootcompiler.
Fix bug with PackWithReplacements when top-level object with complex objects.

PackWithReplacements failed with "Resources found during pickling",
because the original value becomes a Reference after replacemenet.
Merge pull request #227 from kennytm/top-level-pack-with-repl

Fix bug with PackWithReplacements when replacing top-level object with complex values.