Add linters

tools/install_linter

@@ -0,0 +1,11 @@
+#!/bin/bash
+set -x
+
+tools_bin_dir="${BASH_SOURCE%/*}"
+download_url=https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh
+version=v1.29.0
+
+if ! curl -sfL "$download_url" | sh -s -- -b "$tools_bin_dir/bin" "$version"; then
+  printf "Something went wrong while installing golangci-lint\n" 1>&2
+  exit 1
+fi

tools/whitespace_linter

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+
+# git 1.9.0+ allows for exclusions in pathspecs via ':!foo' syntax.
+# However, until git 2.13.0 there must be at least one "inclusive" pathspec, hence the './*'
+trailing_whitespace=$(git grep -E -n -- ' +$' -- './*' ':!*.png')
+
+if [[ -n "$trailing_whitespace" ]]; then
+  printf "ERROR: Trailing whitespaces:\n"
+  awk 'BEGIN {FS=":"} {printf " * %s:%s\n", $1, $2}' <<< "$trailing_whitespace"
+  exit 1
+fi