- Refactored TankDrive and ArcadeDrive to implement a Drive interface.
- Created an integer value in Robot to indicate which drive method is being used. Currently this is hardcoded to ArcadeDrive, but in the future could be determined by a config file or from the driver station.
- Rewrote the ArcadeDrive calculations. Will document/comment changes later.
Commented the ArcadeDrive calculations.
Merge remote-tracking branch 'origin/Refactoring-Drive-Code'

Conflicts:
	2815Robot/src/edu/wpi/first/wpilibj/ArcadeDrive.java
	2815Robot/src/edu/wpi/first/wpilibj/Robot.java
	2815Robot/src/edu/wpi/first/wpilibj/TankDrive.java