Split travis into multiple jobs (#322)

The motivation for this is to make it easier to see whether a travis failure is due to linting, unit tests or integration test failures, without having to look in the logs.

It also means that each job is independent, so if e.g. the linting fails then the unit tests will still be run.

.travis.yml

@@ -1,6 +1,12 @@
 language: go
 go:
  - 1.8
+ - 1.9
+
+env:
+- TEST_SUITE="lint"
+- TEST_SUITE="unit-test"
+- TEST_SUITE="integ-test"
 
 sudo: false
 
@@ -8,9 +14,6 @@ sudo: false
 dist: trusty
 
 addons:
-  apt:
-    packages:
-    - openssl
   postgresql: "9.5"
 
 services:
@@ -19,12 +22,7 @@ services:
 install:
  - go get github.com/constabulary/gb/...
 
-# Generate a self-signed X.509 certificate for TLS.
-before_script:
- - openssl req -x509 -newkey rsa:4096 -keyout server.key -out server.crt -days 365 -nodes -subj /CN=localhost
-
 script:
- - ./scripts/install-local-kafka.sh
  - ./scripts/travis-test.sh
 
 notifications: