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/tree_blob.go

@@ -0,0 +1,57 @@
+// 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 (
+	"path"
+	"strings"
+)
+
+func (t *Tree) GetTreeEntryByPath(relpath string) (*TreeEntry, error) {
+	if len(relpath) == 0 {
+		return &TreeEntry{
+			ID:   t.ID,
+			Type: OBJECT_TREE,
+			mode: ENTRY_MODE_TREE,
+		}, nil
+	}
+
+	relpath = path.Clean(relpath)
+	parts := strings.Split(relpath, "/")
+	var err error
+	tree := t
+	for i, name := range parts {
+		if i == len(parts)-1 {
+			entries, err := tree.ListEntries()
+			if err != nil {
+				return nil, err
+			}
+			for _, v := range entries {
+				if v.name == name {
+					return v, nil
+				}
+			}
+		} else {
+			tree, err = tree.SubTree(name)
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+	return nil, ErrNotExist{"", relpath}
+}
+
+func (t *Tree) GetBlobByPath(relpath string) (*Blob, error) {
+	entry, err := t.GetTreeEntryByPath(relpath)
+	if err != nil {
+		return nil, err
+	}
+
+	if !entry.IsDir() {
+		return entry.Blob(), nil
+	}
+
+	return nil, ErrNotExist{"", relpath}
+}