Add e2e tests

vendor/github.com/gogo/protobuf/extensions.md

@@ -20,8 +20,8 @@ See [BenchComparison](https://github.com/gogo/protobuf/blob/master/bench.md) for
 <tr><td><a href="http://godoc.org/github.com/gogo/protobuf/plugin/size">sizer</a></td><td>Message</td><td>bool</td><td>if true, a Size method is generated for the specific message</td><td>false</td></tr>
 <tr><td><a href="http://godoc.org/github.com/gogo/protobuf/plugin/unmarshal">unmarshaler</a></td><td> Message </td><td> bool </td><td> if true, an Unmarshal method is generated for the specific message </td><td> false</td></tr>
 <tr><td><a href="http://godoc.org/github.com/gogo/protobuf/plugin/size">protosizer</a></td><td>Message</td><td>bool</td><td>if true, a ProtoSize method is generated for the specific message</td><td>false</td></tr>
-<tr><td><a href="http://godoc.org/github.com/gogo/protobuf/plugin/marshalto"> unsafe_marshaler</a> </td><td> Message </td><td> bool </td><td> if true, a Marshal and MarshalTo method is generated for the specific message. The generated code uses the unsafe package and is not compatible with big endian CPUs. </td><td> false</td></tr>
-<tr><td><a href="http://godoc.org/github.com/gogo/protobuf/plugin/unmarshal">unsafe_unmarshaler</a></td><td> Message </td><td> bool </td><td> if true, an Unmarshal method is generated for the specific message. The generated code uses the unsafe package and is not compatible with big endian CPUs. </td><td> false</td></tr>
+<tr><td><a href="http://godoc.org/github.com/gogo/protobuf/plugin/marshalto"> unsafe_marshaler</a> (deprecated) </td><td> Message </td><td> bool </td><td> if true, a Marshal and MarshalTo method is generated. </td><td> false</td></tr>
+<tr><td><a href="http://godoc.org/github.com/gogo/protobuf/plugin/unmarshal">unsafe_unmarshaler</a> (deprecated) </td><td> Message </td><td> bool </td><td> if true, an Unmarshal method is generated. </td><td> false</td></tr>
 <tr><td><a href="http://godoc.org/github.com/gogo/protobuf/plugin/marshalto">stable_marshaler</a></td><td> Message </td><td> bool </td><td> if true, a Marshal and MarshalTo method is generated for the specific message, but unlike marshaler the output is guaranteed to be deterministic, at the sacrifice of some speed</td><td> false </td></tr>
 <tr><td>typedecl (beta)</td><td> Message </td><td> bool </td><td> if false, type declaration of the message is excluded from the generated output. Requires the marshaler and unmarshaler to be generated.</td><td> true </td></tr>
 </table>
@@ -69,6 +69,7 @@ The enumprefix, getters and stringer extensions can be used to remove some of th
 <tr><td> goproto_enum_stringer (experimental) </td><td> Enum </td><td> bool </td><td> if false, the enum is generated without the default string method, this is useful for rather using enum_stringer </td><td> true </td></tr>
 <tr><td> goproto_extensions_map (beta) </td><td> Message </td><td> bool </td><td> if false, the extensions field is generated as type []byte instead of type map[int32]proto.Extension </td><td> true </td></tr>
 <tr><td> goproto_unrecognized (beta) </td><td> Message </td><td> bool </td><td>if false, XXX_unrecognized field is not generated. This is useful to reduce GC pressure at the cost of losing information about unrecognized fields. </td><td> true </td></tr>
+<tr><td> goproto_registration (beta) </td><td> File </td><td> bool </td><td>if true, the generated files will register all messages and types against both gogo/protobuf and golang/protobuf. This is necessary when using third-party packages which read registrations from golang/protobuf (such as the grpc-gateway). </td><td> false </td></tr>
 </table>
 
 # Less Typing