Bump expected 2.11 module versions so we can compile with 2.11

Add scala 2.11 test/build verification.

* Add 2.11 build configuratoin to travis ci
* Create command which runs `safe` unit tests
* Create command to test the scala 2.11 build
* Update scalacheck to 1.11.4
* Update specs2 to 2.3.11
* Fix various 2.11/deprecation removals
  and other changes.

Fix eval test failure in scala 2.11 with XML not existing.
Merge pull request #1336 from sbt/wip/compile-with-2.11

Bump expected 2.11 module versions so we can compile with 2.11