Refactor Travis to run all tests in parallel
Refactor Travis to run all tests in parallel

This avoids each kitchen test also running the linting. Now every kind of
test is its own sub-build!

SimpleFinance/chef-zookeeper,evertrue/zookeeper-cookbook,evertrue/zookeeper-cookbook,SimpleFinance/chef-zookeeper,criteo-forks/chef-zookeeper,SimpleFinance/chef-zookeeper,evertrue/zookeeper-cookbook