Adds exclusions to surefire tests in order to avoid headless exceptions during build.
<groupId>org.apache.maven.surefire</groupId>
<artifactId>surefire</artifactId>
<version>2.21.0</version>
+ <configuration>
+ <excludes>
+ <exclude>**/TileTest/DrawTest.java</exclude>
+ <exclude>**/misc/ImageCacheTest.java</exclude>
+ </excludes>
+ </configuration>
</plugin>
</plugins>
</build>
