Update building stuff

- Add a Makefile with common targets (binary, test, validate, ..)
- Use docker to build it (isolated)

And update circleci to work with the new Makefile..

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

script/test-unit

@@ -0,0 +1,56 @@
+#!/bin/bash
+set -e
+
+if ! test -e gen.go; then
+	echo >&2 'error: generate must be run before binary'
+	false
+fi
+
+RED=$'\033[31m'
+GREEN=$'\033[32m'
+TEXTRESET=$'\033[0m' # reset the foreground colour
+
+# This helper function walks the current directory looking for directories
+# holding certain files ($1 parameter), and prints their paths on standard
+# output, one per line.
+find_dirs() {
+    find . -not \( \
+         \( \
+         -path './integration/*' \
+         -o -path './.git/*' \
+         \) \
+         -prune \
+         \) -name "$1" -print0 | xargs -0n1 dirname | sort -u
+}
+
+TESTFLAGS="-cover -coverprofile=cover.out ${TESTFLAGS}"
+
+if [ -z "$TESTDIRS" ]; then
+    TESTDIRS=$(find_dirs '*_test.go')
+fi
+
+TESTS_FAILED=()
+
+for dir in $TESTDIRS; do
+    echo '+ go test' $TESTFLAGS "${dir}"
+    go test ${TESTFLAGS} ${dir}
+    if [ $? != 0 ]; then
+        TESTS_FAILED+=("$dir")
+        echo
+        echo "${RED}Tests failed: $dir${TEXTRESET}"
+        sleep 1 # give it a second, so observers watching can take note
+    fi
+done
+echo
+
+# if some tests fail, we want the bundlescript to fail, but we want to
+# try running ALL the tests first, hence TESTS_FAILED
+if [ "${#TESTS_FAILED[@]}" -gt 0 ]; then
+    echo "${RED}Test failures in: ${TESTS_FAILED[@]}${TEXTRESET}"
+    echo
+    false
+else
+    echo "${GREEN}Test success${TEXTRESET}"
+    echo
+    true
+fi