Add travis support

.travis.yml

+language: ruby
+sudo: false
+cache: bundler
+before_install:
+ - git clone https://github.com/jnavila/po4a.git
+ - cd po4a && git checkout git_doc && cd ..
+script:
+ - sh ci/build.sh
+addons:
+  apt:
+    packages:
+      - libunicode-linebreak-perl
+notifications:
+  email:
+    on_success: never
+    on_failure: always

Gemfile

+source 'https://rubygems.org'
+
+gem 'asciidoctor', '1.5.6.1'
+
+gem 'json'
+gem 'awesome_print'
+
+gem 'asciidoctor-epub3', :git => 'https://github.com/asciidoctor/asciidoctor-epub3'
+gem 'asciidoctor-pdf', '1.5.0.alpha.16'
+gem 'asciidoctor-pdf-cjk', '~> 0.1.3'
+gem 'asciidoctor-pdf-cjk-kai_gen_gothic', '~> 0.1.1'
+
+gem 'coderay'
+gem 'pygments.rb'
+gem 'thread_safe'

ci/build.sh

+#!/bin/sh
+
+export PERLLIB=$(pwd)/po4a/lib
+export PERL5LIB=$(pwd)/po4a/lib
+export PATH=$PATH:$(pwd)/po4a
+bundle exec make all