This does not deprecate any current functionality, but prepares the way for future deprecation.
The drive classes now accept void(double) functions, which makes them more flexible.
The C++ API ended up a bit more verbose, but the Java API is really concise with method references, which is >80% of our userbase. For example:
`DifferentialDrive drive = new DifferentialDrive(m_leftMotor::set, m_rightMotor::set);`
Lambdas can be passed to interoperate with vendor motor controller APIs that don't have e.g., set(double), so CTRE doesn't have to maintain their WPI_ classes anymore.
MotorControllerGroup was replaced with PWMMotorController.addFollower() for PWM motor controllers. Users of CAN motor controllers should use their vendor's follower functionality.
To reduce the need for users to manually perform unit conversions, this allows Measure objects from wpiunits to be passed into most places in wpimath that currently expect doubles in terms of SI units like meters.
For example, users would need to know that unit conversion is required - and what the correct units are. Using units would be more difficult to write code for than just hardcoding a value or using Units.inchesToMeters.
Now, using units has no more developer overhead than using raw numbers.
