Removing deprecated "re-publish release artifacts" behavior from tests.

In sbt 1.0 republishing released artifacts will be removed, causing these tests
to fail.  We migrate to SNAPSHOT version now, to prevent suprises.
First attempt at travis-ci integration for sbt.
Merge branch 'wip/travis-test' into wip/fix-deprecated-ivy-in-test
For now only run integration tests from travis (OoM errors).
Split scripted tests into matrix so we run on parallel virtual machines.
Merge pull request #1162 from sbt/wip/fix-deprecated-ivy-in-test

Removing deprecated "re-publish release artifacts" behavior from tests.