chore: Use dep as dependency management tool.

.gitignore

@@ -3,3 +3,4 @@ debug.test
 coverage.out
 .idea/
 *.swp
+vendor/

.travis.yml

@@ -1,16 +1,24 @@
 language: go
 
 go:
-    - 1.8
+  - 1.8.x
+  - 1.9.x
+  - master
 
 sudo: false
 
+before_install:
+  - curl -sI https://github.com/golang/dep/releases/latest | grep -Fi Location  | tr -d '\r' | sed "s/tag/download/g" | awk -F " " '{ print $2 "/dep-linux-amd64"}' | wget --output-document=$GOPATH/bin/dep -i -
+  - chmod +x $GOPATH/bin/dep
+
 install:
-    - go get -d -v ./...
-    - go get github.com/mattn/goveralls
+  - dep ensure -v
+  - go get github.com/mattn/goveralls
 
 script:
-    - GOOS=darwin go build
-    - GOOS=windows go build
-    - GOOS=linux go build
-    - $HOME/gopath/bin/goveralls -service=travis-ci
+  - PKGS=$(go list ./... | grep -v '/vendor/')
+  - go test -v -cover $PKGS
+  - GOOS=darwin go build
+  - GOOS=windows go build
+  - GOOS=linux go build
+  - $HOME/gopath/bin/goveralls -service=travis-ci

Gopkg.toml

@@ -0,0 +1,26 @@
+
+# Gopkg.toml example
+#
+# Refer to https://github.com/golang/dep/blob/master/docs/Gopkg.toml.md
+# for detailed Gopkg.toml documentation.
+#
+# required = ["github.com/user/thing/cmd/thing"]
+# ignored = ["github.com/user/project/pkgX", "bitbucket.org/user/project/pkgA/pkgY"]
+#
+# [[constraint]]
+#   name = "github.com/user/project"
+#   version = "1.0.0"
+#
+# [[constraint]]
+#   name = "github.com/user/project2"
+#   branch = "dev"
+#   source = "github.com/myfork/project2"
+#
+# [[override]]
+#  name = "github.com/x/y"
+#  version = "2.4.0"
+
+
+[[constraint]]
+  name = "github.com/ogier/pflag"
+  branch = "master"