Add a Go language example.

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.

1 files changed, 21 insertions, 0 deletions

diff --git a/examples/Makefile b/examples/Makefile
index 8dc90836..51f13426 100644
--- a/examples/Makefile
+++ b/examples/Makefile
@@ -5,6 +5,8 @@
 all: cpp java python
 
 cpp:    add_person_cpp    list_people_cpp
+go:     add_person_go     list_people_go
+gotest: add_person_gotest list_people_gotest
 java:   add_person_java   list_people_java
 python: add_person_python list_people_python
 
@@ -13,6 +15,8 @@ clean:
 	rm -f javac_middleman AddPerson*.class ListPeople*.class com/example/tutorial/*.class
 	rm -f protoc_middleman addressbook.pb.cc addressbook.pb.h addressbook_pb2.py com/example/tutorial/AddressBookProtos.java
 	rm -f *.pyc
+	rm -f protoc_middleman_go tutorial/*.pb.go add_person_go list_people_go
+	rmdir tutorial 2>/dev/null || true
 	rmdir com/example/tutorial 2>/dev/null || true
 	rmdir com/example 2>/dev/null || true
 	rmdir com 2>/dev/null || true
@@ -21,6 +25,11 @@ protoc_middleman: addressbook.proto
 	protoc --cpp_out=. --java_out=. --python_out=. addressbook.proto
 	@touch protoc_middleman
 
+protoc_middleman_go: addressbook.proto
+	mkdir tutorial # make directory for go package
+	protoc --go_out=tutorial addressbook.proto
+	@touch protoc_middleman_go
+
 add_person_cpp: add_person.cc protoc_middleman
 	pkg-config --cflags protobuf  # fails if protobuf is not installed
 	c++ add_person.cc addressbook.pb.cc -o add_person_cpp `pkg-config --cflags --libs protobuf`
@@ -29,6 +38,18 @@ list_people_cpp: list_people.cc protoc_middleman
 	pkg-config --cflags protobuf  # fails if protobuf is not installed
 	c++ list_people.cc addressbook.pb.cc -o list_people_cpp `pkg-config --cflags --libs protobuf`
 
+add_person_go: add_person.go protoc_middleman_go
+	go build -o add_person_go add_person.go
+
+add_person_gotest: add_person_test.go add_person_go
+	go test add_person.go add_person_test.go
+
+list_people_go: list_people.go protoc_middleman_go
+	go build -o list_people_go list_people.go
+
+list_people_gotest: list_people.go list_people_go
+	go test list_people.go list_people_test.go
+
 javac_middleman: AddPerson.java ListPeople.java protoc_middleman
 	javac AddPerson.java ListPeople.java com/example/tutorial/AddressBookProtos.java
 	@touch javac_middleman