Bump protobuf and plugins versions

Bump protobuf version and add build tools

• Protobuf 3.6.0
• Gen doc 1.1.0
• Scalapb 0.7.4
• Rust protobuf 2.0.3
• Java 8.8u181
• Alpine 3.8

This release includes a important fix by @marcelbuesing which makes possible to use --proto_path /usr/local/include to import google's protos like timestamp.proto, before that the user needed to download and include google protos into theirs resources:

$(protobuf-tools) scalapbc --scala_out=flat_package:/tmp \
  --proto_path /usr/local/include --proto_path fixtures ${FIXTURES}

More details https://github.com/brennovich/protobuf-tools/blob/master/Makefile#L20

Fix protoc permissions

cbdd9b0 Fix protoc permissions

Rust plugin & protoc-gen-doc update

c8aec92 Bump protoc-gen-doc to latest version
3cdac74 Add rust-protobuf 1.4.2

• Update protobuf to 3.5.0
• Update scalapb to 0.6.6
• Update gen-doc to latest version (ported to go)
  • This made possible get ride of qt dependency and use pre-built
    version of protobuf

Updates and protoc-gen-go

• Alpine 3.6
• Protobuf 3.3.1
• Latest Java
• Add protoc-gen-go plugin

Scala generator

Add Scala generate resources support through ScalaPB

First Version

In this first version we introduce:

• protobuf 3.0.2
• protoc-gen-doc trunk