Add Drivebase and Related Code

[timtim17]

• [x] Make a Subsystem for the Drivebase
  • It is safe to assume that we are using at least two TalonSRXs, one for each side.
  • WPILib's drive classes have changed.
  • You can combine multiple motor controllers into a MotorControllerGroup, one per side.
  • The old RobotDrive class is now deprecated. Since we are designing a WCD, we will use a DifferentialDrive. Look this up in the Javadoc for WPILib.
• [ ] Create drive Commands
  • The exact drive scheme the driver will use depends on who is ultimately our driver. For now, create a few basic Commands:
  • [ ] Tank Drive (DifferentialDrive.tankDrive())
  • [x] Arcade Drive (DifferentialDrive.arcadeDrive())
• [ ] Gear Shifting (to be confirmed, but this doesn't seem like a thing anymore?)
  • TBD by design teams.
  • Robot should have the capability to shift between low and high gears, and have some logic to:
  • ...automatically shift to high gear when the robot is going ~6 m/s
  • ...restrict switching to low gear when the robot is moving too slow.
  • Assume there is a NavX or other accelerometer (the built-in roboRIO accelerometer?) to report the velocity of the robot.

[timtim17]

Tank drive appears to be unnecessary, and gear shifting doesn't seem to be a thing. This issue is basically resolved.