switch to dep and integrate cobra

vendor/github.com/spf13/cobra/.travis.yml

@@ -0,0 +1,21 @@
+language: go
+
+matrix:
+  include:
+    - go: 1.7.6
+    - go: 1.8.3
+    - go: tip
+  allow_failures:
+    - go: tip
+
+before_install:
+  - mkdir -p bin
+  - curl -Lso bin/shellcheck https://github.com/caarlos0/shellcheck-docker/releases/download/v0.4.3/shellcheck
+  - chmod +x bin/shellcheck
+script:
+  - PATH=$PATH:$PWD/bin go test -v ./...
+  - go build
+  - diff -u <(echo -n) <(gofmt -d -s .)
+  - if [ -z $NOVET ]; then
+      diff -u <(echo -n) <(go tool vet . 2>&1 | grep -vE 'ExampleCommand|bash_completions.*Fprint');
+    fi