CANJaguar is the only motor controller using sync groups, so that feature doesn't belong in an interface used by all motor controllers. If teams want to use sync groups, they should cast to the appropriate motor controller type themselves.
Rename the following folders:
hal/lib/Athena -> hal/lib/athena
hal/lib/Desktop -> hal/lib/sim
hal/lib/Shared -> hal/lib/shared
wpilibc/Athena -> wpilibc/athena
wpilibc/simulation -> wpilibc/sim
Windows users may need to run gradlew clean after updating.
