Support system / integration tests

[oubiwann]

• Decide upon a system / integration test strategy that runs on Travis CI - see Decide upon a system / integration test strategy that runs on Travis CI #44
• Create the necessary Clojure glue for the selected approach (clojure.test-compatible) - see Write clojure.test compatible layer for sys/int testing #45
• Create some basic integration tests, targeted initially at just the changes between 0.28.2 and 1.0.1 - see Create integration tests for just the changes between 0.28.0 and 1.0.1 #46