Add zip2zip tool to copy zip entries from one file to another

This doesn't do any decompression / recompression, but just copies over
the already compressed contents. So it's similar to zip -U, but allows
rewriting of the paths.

The first expected usecase is to replace img_from_target_files during
the build, since it does the equivalent of this:

zip2zip -i <target-files.zip> -o <img.zip> OTA/android-info.txt:android-info.txt IMAGES/*:.

Except it decompresses and recompresses the images, which takes over a
minute instead of a few seconds.

Change-Id: I88d0df188635088783223873f78e193272dbdf1c

third_party/zip/Android.bp

@@ -0,0 +1,31 @@
+// Copyright 2016 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+bootstrap_go_package {
+    name: "android-archive-zip",
+    pkgPath: "android/soong/third_party/zip",
+    srcs: [
+        "reader.go",
+        "register.go",
+        "struct.go",
+        "writer.go",
+
+        "android.go",
+    ],
+    testSrcs: [
+        "reader_test.go",
+        "writer_test.go",
+        "zip_test.go",
+    ],
+}