Signed-off-by: Xiang Dai <764524258@qq.com>

To make this work, I created a symlink to the existing zlib.BUILD file.
Maybe there is a better way to do this, but this is at least a quick
workaround to fix the build.

To make this work, I created a symlink to the existing zlib.BUILD file.
Maybe there is a better way to do this, but this is at least a quick
workaround to fix the build.

Fixed typo in a function name.

@bazel_skylib//:lib is supposedly deprecated. The 'versions' struct in lib.bzl was committed to bazel-skylib at the same time as //lib:versions.bzl, so there should be no backward incompatibility.

It needs "-I" flag to find imported file google/protobuf/timestamp.proto

The example utilizes native bazel rules (proto_library, cc_proto_library,
java_proto_library, java_lite_proto_library) to show how easy it is to
build protobuf with bazel's native support. It also makes use of well
known types which was not possible until the latest bazel 0.5.4 release
and https://github.com/google/protobuf/pull/3594 .

The future import is required to support the print(x, end=" ") parameter in Python 2.

A series of improvements:

- Improved Protobuf module compatibility (disabled by default);
- Hide advanced settings;
- Added build tree configuration;
- Added build of examples.

This will allow us to like to specific snippets of code in the
documentation.  I plan to create a tutorial similar to the C# tutorial
https://developers.google.com/protocol-buffers/docs/csharptutorial

Since that tutorial has sections for populating a proto, parsing, and
serializing, I made a region for each of these for Go.  To make the
populating sample more self-contained, I refactor the listing example
slightly.

Since these tags might be confusing, added a note that these are not
part of the normal protocol buffers syntax.  I also linked to the main
tutorials page that uses these examples
https://developers.google.com/protocol-buffers/docs/tutorials so that
anyone who arrived here without going through that info first can get
more explanation if they want.

This follows the other examples so that it can be used as a tutorial,
such as the ones at:
  https://developers.google.com/protocol-buffers/docs/tutorials

Even though Go generally does not use Makefiles, I added targets for the
Go examples to be consistent with the other languages.

Edit:

Fix Travis run. Change to use $HOME instead of ~. Add protoc to path.
GOPATH entry cannot start with shell metacharacter '~': "~/gocode"

Edit(2):

Fix Go code style to address comments.

Note that now we need a proto3 version of addressbook.proto. This may affect other platforms, and could do with an overhaul to follow proto3 conventions anyway (e.g. repeated field names). Will need to think about that carefully before merging into master. Raised issue #565 for this.

- Remove some old proto2-based C#-only messages
- Remove the "build" directory which only contained out-of-date files
- Remove the csharp_namespace option from proto2 messages
- Change "Google.ProtocolBuffers" to "Google.Protobuf" in other messages