add basic travis-ci support (#32)

- travis-ci/travis-ci#5176 (comment)
- travis-ci/travis-ci#3701 (comment)
- https://docs.travis-ci.com/user/installing-dependencies/#Installing-Packages-on-Standard-Infrastructure
- orphan-oss/launch4j-maven-plugin#30 (comment)
- http://stackoverflow.com/a/23622067/1128689

.travis.yml

@@ -0,0 +1,10 @@
+language: java
+jdk:
+  - oraclejdk8
+  - oraclejdk7
+sudo: required
+install: true
+before_script:
+  - sudo apt-get -qq update
+  - sudo apt-get install -y lib32z1 lib32ncurses5 lib32bz2-1.0
+script: mvn -Dmaven.codesign.skip=true clean verify