Update import paths from github.com/go-gitea to code.gitea.io (#135)

- Update import paths from github.com/go-gitea to code.gitea.io
- Fix import path for travis

See https://docs.travis-ci.com/user/languages/go#Go-Import-Path

vendor/code.gitea.io/git/sha1.go

@@ -0,0 +1,93 @@
+// Copyright 2015 The Gogs Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package git
+
+import (
+	"encoding/hex"
+	"fmt"
+	"strings"
+)
+
+const EMPTY_SHA = "0000000000000000000000000000000000000000"
+
+type sha1 [20]byte
+
+// Equal returns true if s has the same sha1 as caller.
+// Support 40-length-string, []byte, sha1.
+func (id sha1) Equal(s2 interface{}) bool {
+	switch v := s2.(type) {
+	case string:
+		if len(v) != 40 {
+			return false
+		}
+		return v == id.String()
+	case []byte:
+		if len(v) != 20 {
+			return false
+		}
+		for i, v := range v {
+			if id[i] != v {
+				return false
+			}
+		}
+	case sha1:
+		for i, v := range v {
+			if id[i] != v {
+				return false
+			}
+		}
+	default:
+		return false
+	}
+	return true
+}
+
+// String returns string (hex) representation of the Oid.
+func (s sha1) String() string {
+	result := make([]byte, 0, 40)
+	hexvalues := []byte("0123456789abcdef")
+	for i := 0; i < 20; i++ {
+		result = append(result, hexvalues[s[i]>>4])
+		result = append(result, hexvalues[s[i]&0xf])
+	}
+	return string(result)
+}
+
+// MustID always creates a new sha1 from a [20]byte array with no validation of input.
+func MustID(b []byte) sha1 {
+	var id sha1
+	for i := 0; i < 20; i++ {
+		id[i] = b[i]
+	}
+	return id
+}
+
+// NewID creates a new sha1 from a [20]byte array.
+func NewID(b []byte) (sha1, error) {
+	if len(b) != 20 {
+		return sha1{}, fmt.Errorf("Length must be 20: %v", b)
+	}
+	return MustID(b), nil
+}
+
+// MustIDFromString always creates a new sha from a ID with no validation of input.
+func MustIDFromString(s string) sha1 {
+	b, _ := hex.DecodeString(s)
+	return MustID(b)
+}
+
+// NewIDFromString creates a new sha1 from a ID string of length 40.
+func NewIDFromString(s string) (sha1, error) {
+	var id sha1
+	s = strings.TrimSpace(s)
+	if len(s) != 40 {
+		return id, fmt.Errorf("Length must be 40: %s", s)
+	}
+	b, err := hex.DecodeString(s)
+	if err != nil {
+		return id, err
+	}
+	return NewID(b)
+}