Add Travis CI Build Status and YAML

Add ant-optional, Travis omits JUnit by default
    Add git ignore entry for MACOS .DS_Store files
    Add Travis CI yml file for testing builds

    https://travis-ci.org/FreeCol/freecol

.gitignore

@@ -23,6 +23,7 @@ a/
 b/
 TESTS-TestSuites.xml
 freecol.jar
+.DS_Store
 
 ### Java template
 

.travis.yml

@@ -0,0 +1,9 @@
+language: java
+
+jdk:
+  - oraclejdk8
+
+addons:
+  apt:
+    packages:
+      - ant-optional

README.md

@@ -1,4 +1,4 @@
-# freecol
+# FreeCol [![Build Status](https://travis-ci.org/FreeCol/freecol.svg?branch=master)](https://travis-ci.org/FreeCol/freecol)
 
 FreeCol is a turn-based strategy game based on the old game
 Colonization, and similar to Civilization. The objective of the game is
@@ -8,7 +8,7 @@ You start with only a few colonists defying the stormy seas in their
 search for new land. Will you guide them on the Colonization of a New
 World?
 
-## About FreeCol 
+## About FreeCol
 
 The FreeCol team aims to create an Open Source version of Colonization
 (released under the GPL). At first we'll try to make an exact clone of