Clean up the scripts a bit (...)

- Move the Go files into script/ instead of random places
- Rewrite check-contrib.sh into check-authors.go and check-copyright.go
- Clean up build.sh a little bit

script/check-copyright.go

@@ -0,0 +1,72 @@
+// Copyright (C) 2015 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build ignore
+
+// Checks for files missing copyright notice
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+// File extensions to check
+var checkExts = map[string]bool{
+	".go": true,
+}
+
+// Valid copyright headers, searched for in the top five lines in each file.
+var copyrightRegexps = []string{
+	`Copyright`,
+	`package auto`,
+	`automatically generated by genxdr`,
+}
+
+var copyrightRe = regexp.MustCompile(strings.Join(copyrightRegexps, "|"))
+
+func main() {
+	flag.Parse()
+	for _, dir := range flag.Args() {
+		err := filepath.Walk(dir, checkCopyright)
+		if err != nil {
+			fmt.Println(err)
+			os.Exit(1)
+		}
+	}
+}
+
+func checkCopyright(path string, info os.FileInfo, err error) error {
+	if err != nil {
+		return err
+	}
+	if !info.Mode().IsRegular() {
+		return nil
+	}
+	if !checkExts[filepath.Ext(path)] {
+		return nil
+	}
+
+	fd, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer fd.Close()
+
+	scanner := bufio.NewScanner(fd)
+	for i := 0; scanner.Scan() && i < 5; i++ {
+		if copyrightRe.MatchString(scanner.Text()) {
+			return nil
+		}
+	}
+
+	return fmt.Errorf("Missing copyright in %s?", path)
+}