Improved Command-based examples (#906)

Robot.cpp has been split into header-source pairs and the Command-based
examples now define an example subsystem in the Robot class.

wpilibcExamples/src/main/cpp/templates/commandbased/Commands/ExampleCommand.cpp

@@ -7,9 +7,11 @@
 
 #include "ExampleCommand.h"
 
+#include "../Robot.h"
+
 ExampleCommand::ExampleCommand() {
 	// Use Requires() here to declare subsystem dependencies
-	// eg. Requires(&Robot::chassis);
+	Requires(&Robot::m_subsystem);
 }
 
 // Called just before this Command runs the first time