Generate AprilTags in custom layouts for AprilTag 3.
Example usage for generating the 21h7 circular tag family:
$ ant
$ java -cp april.jar april.tag.TagFamilyGenerator circle_9 7
Then to generate the c code and tag images after copying the output into the source folder:
$ ant
$ java -cp april.jar april.tag.TagToC april.tag.TagCircle21h7
$ java -cp april.jar april.tag.GenerateTags april.tag.TagCircle21h7 .