It would be good if it was mentioned anywhere that you need a ToughAsNails.jar external dependency to build DynamicSurroundings.
Likewise, it also wouldn't hurt if the empty lib folder and modified gradle.build (containing compile fileTree(dir: 'lib', includes: ['*.jar']) ) were pushed to the repo too, as modifying those manually means trouble since it makes the local git working state unclean - preventing a pull.

I went ahead and checked the JAR in the libs directory for now w/the appropriate TAN jar. I have it on my list to clean up API dependencies a bit. Some work I have to do.

Modified build to pull TaN from maven repository. Should address this nicely.