Lock binary dependencies to a specific commits / versions

This is basically copying over @anton's great script!

Also had to run `make format` to make this pass `test_lint`.
This PR also makes the make commands for tools further align
with the tendermint implementation.

scripts/get_tools.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+set -e
+
+# This file downloads all of the binary dependencies we have, and checks out a
+# specific git hash.
+#
+# repos it installs:
+#   github.com/mitchellh/gox
+#   github.com/golang/dep/cmd/dep
+#   gopkg.in/alecthomas/gometalinter.v2
+#   github.com/gogo/protobuf/protoc-gen-gogo
+#   github.com/square/certstrap
+
+## check if GOPATH is set
+if [ -z ${GOPATH+x} ]; then
+	echo "please set GOPATH (https://github.com/golang/go/wiki/SettingGOPATH)"
+	exit 1
+fi
+
+mkdir -p "$GOPATH/src/github.com"
+cd "$GOPATH/src/github.com" || exit 1
+
+installFromGithub() {
+	repo=$1
+	commit=$2
+	# optional
+	subdir=$3
+	echo "--> Installing $repo ($commit)..."
+	if [ ! -d "$repo" ]; then
+		mkdir -p "$repo"
+		git clone "https://github.com/$repo.git" "$repo"
+	fi
+	if [ ! -z ${subdir+x} ] && [ ! -d "$repo/$subdir" ]; then
+		echo "ERROR: no such directory $repo/$subdir"
+		exit 1
+	fi
+	pushd "$repo" && \
+		git fetch origin && \
+		git checkout -q "$commit" && \
+		if [ ! -z ${subdir+x} ]; then cd "$subdir" || exit 1; fi && \
+		go install && \
+		if [ ! -z ${subdir+x} ]; then cd - || exit 1; fi && \
+		popd || exit 1
+	echo "--> Done"
+	echo ""
+}
+
+installFromGithub golang/dep 22125cfaa6ddc71e145b1535d4b7ee9744fefff2 cmd/dep
+## gometalinter v2.0.11
+installFromGithub alecthomas/gometalinter 17a7ffa42374937bfecabfb8d2efbd4db0c26741
+installFromGithub rakyll/statik v0.1.5