Update Travis recipe
Add travis credentials
Squashed 'core/' changes from abb737c..535c35e

535c35e Allow multiple JAR uploads in plugins

git-subtree-dir: core
git-subtree-split: 535c35e1788773b68c72de539740b7916a0a5d74
Merge commit '06a3b2b8e76e252928e3f826cb79dc038c381337' into feature/multiarch