ci: add travis

Jenkins is EOL at this point.

.travis.yml

+sudo: false
+
+
+language: go
+go:
+  - 1.11.x
+
+before_install:
+  - make deps
+
+script:
+  - bash <(curl -s https://raw.githubusercontent.com/ipfs/ci-helpers/master/travis-ci/run-standard-tests.sh)
+
+after_success:
+  - bash <(curl -s https://codecov.io/bash)
+
+cache:
+  directories:
+    - $GOPATH/src/gx
+
+notifications:
+  email: false

Makefile

+gx:
+	go get github.com/whyrusleeping/gx
+	go get github.com/whyrusleeping/gx-go
+
+deps: gx
+	gx --verbose install --global
+	gx-go rewrite
+
+publish:
+	gx-go rewrite --undo
+