Most importantly, it will probably not even build or include all the current code.
While the source is for everyone to inspect, copyright on it is held by Lyinginbedmon and as it currently stands you are not allowed to reuse this code in any way shape or form.
This README was written by The Flying Bun, Lying did not contribute to it so far
# If you want to test it
./gradlew runClient
# or depending on your platform
gradlew.bat runClient
# For other possible build system calls use
./gradlew tasks
# or
gradlew.bat tasks