freeze Go build dependencies in Gopkg.lock

* use pseudo-depdencies in build/build.go to convince dep
* update Travis, Dockerfile and Docs
* build.Dockerfile image now contains the Go build dependencies
* => faster builds
* bump pdu file after protoc update

fixes #106

Gopkg.lock

@@ -1,6 +1,14 @@
 # This file is autogenerated, do not edit; changes may be undone by the next 'dep ensure'.
 
 
+[[projects]]
+  branch = "master"
+  digest = "1:8cf2cf1ab10480b5e0df950dac1517aaabde05d055d9d955652997ae4b9ecbbf"
+  name = "github.com/alvaroloes/enumer"
+  packages = ["."]
+  pruneopts = ""
+  revision = "6bcfe2edaac32ad71b88ce4cf92d34cd643e4ecb"
+
 [[projects]]
   branch = "master"
   digest = "1:c0bec5f9b98d0bc872ff5e834fac186b807b656683bd29cb82fb207a1513fabb"
@@ -64,7 +72,15 @@
 [[projects]]
   digest = "1:3dd078fda7500c341bc26cfbc6c6a34614f295a2457149fc1045cab767cbcf18"
   name = "github.com/golang/protobuf"
-  packages = ["proto"]
+  packages = [
+    "proto",
+    "protoc-gen-go",
+    "protoc-gen-go/descriptor",
+    "protoc-gen-go/generator",
+    "protoc-gen-go/generator/internal/remap",
+    "protoc-gen-go/grpc",
+    "protoc-gen-go/plugin",
+  ]
   pruneopts = ""
   revision = "aa810b61a9c79d51363740d207bb46cf8e620ed5"
   version = "v1.2.0"
@@ -141,6 +157,14 @@
   revision = "3247c84500bff8d9fb6d579d800f20b3e091582c"
   version = "v1.0.0"
 
+[[projects]]
+  branch = "master"
+  digest = "1:f60ff065b58bd53e641112b38bbda9d2684deb828393c7ffb89c69a1ee301d17"
+  name = "github.com/pascaldekloe/name"
+  packages = ["."]
+  pruneopts = ""
+  revision = "0fd16699aae1833640fca52a937944c6f3b1d58c"
+
 [[projects]]
   digest = "1:7365acd48986e205ccb8652cc746f09c8b7876030d53710ea6ef7d0bd0dcd7ca"
   name = "github.com/pkg/errors"
@@ -159,7 +183,7 @@
 
 [[projects]]
   branch = "master"
-  digest = "1:1392748e290ca66ac8447ef24961f8ae9e1d846a53af0f58a5a0256982ce0577"
+  digest = "1:25559b520313b941b1395cd5d5ee66086b27dc15a1391c0f2aad29d5c2321f4b"
   name = "github.com/problame/go-netssh"
   packages = ["."]
   pruneopts = ""
@@ -285,14 +309,24 @@
   revision = "f21a4dfb5e38f5895301dc265a8def02365cc3d0"
   version = "v0.3.0"
 
+[[projects]]
+  branch = "master"
+  digest = "1:4cd780b2ee42c8eac9c02bfb6e6b52dcbaef770774458c8938f5cbfb73a7b6d3"
+  name = "golang.org/x/tools"
+  packages = ["cmd/stringer"]
+  pruneopts = ""
+  revision = "d0ca3933b724e6be513276cc2edb34e10d667438"
+
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
   input-imports = [
+    "github.com/alvaroloes/enumer",
     "github.com/fatih/color",
     "github.com/gdamore/tcell/termbox",
     "github.com/go-logfmt/logfmt",
     "github.com/golang/protobuf/proto",
+    "github.com/golang/protobuf/protoc-gen-go",
     "github.com/jinzhu/copier",
     "github.com/kr/pretty",
     "github.com/mattn/go-isatty",
@@ -308,6 +342,7 @@
     "github.com/stretchr/testify/require",
     "github.com/zrepl/yaml-config",
     "golang.org/x/sys/unix",
+    "golang.org/x/tools/cmd/stringer",
   ]
   solver-name = "gps-cdcl"
   solver-version = 1