Removed InternalSetCollectorCommand to change command flow.

Added InternalValveCommand which handles the collector valve.
The command will no longer be improperly interrupted.
Add pusher system to robot.

These commits are based on changes by Eric and were re-added to
fix git history.
Add AssistCommand to operator controls.

This was also a change originally made by Eric.
General code cleanup. NO CODE/LOGIC CHANGES!

Massive import cleanup, removed unnecessary whitespaces, lines, etc.
Add gamepad strafe flip controls to driver gamepad.

The driver can now flip the robot drive direction by holding the
right trigger.
Increase collector speed to full speed.