switch to dep, fix dependencies

- renames dep github.com/codegangsta/cli -> github.com/urfave/cli
- updates dependencies
- ensures all dependencies are included in vendor

Gopkg.toml

@@ -0,0 +1,34 @@
+
+# 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]]
+  branch = "master"
+  name = "github.com/mitchellh/go-homedir"
+
+[[constraint]]
+  name = "github.com/urfave/cli"
+  version = "1.20.0"
+
+[[constraint]]
+  branch = "v2"
+  name = "gopkg.in/yaml.v2"

cmd/karn/karn.go

@@ -4,8 +4,8 @@ import (
 	"log"
 	"os"
 
-	"github.com/codegangsta/cli"
 	"github.com/prydonius/karn"
+	"github.com/urfave/cli"
 )
 
 func main() {