goprotobuf: start making it build with the go tool instead of make.
Work in progress.
This is sufficient to build, install, and test the proto library, and
to build and install the compiler plugin.
The tests for the plugin are disabled; they will require major work in a separate CL.

The compiler directory is now called protoc-gen-go so the binary has the right name.
The test.pb.go file for the proto tests is now checked in, for simplicity.

R=golang-dev, dsymonds
CC=golang-dev
http://codereview.appspot.com/5645087
diff --git a/proto/text_parser_test.go b/proto/text_parser_test.go
index 26bc789..3848790 100644
--- a/proto/text_parser_test.go
+++ b/proto/text_parser_test.go
@@ -35,8 +35,8 @@
 	"reflect"
 	"testing"
 
-	. "./testdata/_obj/test_proto"
 	. "code.google.com/p/goprotobuf/proto"
+	. "code.google.com/p/goprotobuf/proto/testdata"
 )
 
 type UnmarshalTextTest struct {
@@ -192,7 +192,7 @@
 	// Missing required field
 	{
 		in:  ``,
-		err: `line 1.0: message test_proto.MyMessage missing required field "count"`,
+		err: `line 1.0: message testdata.MyMessage missing required field "count"`,
 	},
 
 	// Repeated non-repeated field
@@ -213,9 +213,9 @@
 	},
 
 	// Extension
-	buildExtStructTest(`count: 42 [test_proto.Ext.more]:<data:"Hello, world!" >`),
-	buildExtStructTest(`count: 42 [test_proto.Ext.more] {data:"Hello, world!"}`),
-	buildExtDataTest(`count: 42 [test_proto.Ext.text]:"Hello, world!" [test_proto.Ext.number]:1729`),
+	buildExtStructTest(`count: 42 [testdata.Ext.more]:<data:"Hello, world!" >`),
+	buildExtStructTest(`count: 42 [testdata.Ext.more] {data:"Hello, world!"}`),
+	buildExtDataTest(`count: 42 [testdata.Ext.text]:"Hello, world!" [testdata.Ext.number]:1729`),
 
 	// Big all-in-one
 	{