Hot-Fix: joystick app demo changes

[stephenmcc]

Adds step validity checks to ValkyrieJoystickBasedSteppingApplication: (parameters are found in StepGeneratorJavaFXController)

• Max step up/down of 0.2m
• Max step incline of 45 degrees
• Collision check with same dimensions/logic as footstep planner

Adds png of joystick bindings (XBoxOneControllerStepMapping_noSecondaryOption.png)

Adds joystick bindings for simpler REA control:

• DPad right clears REA
• DPad left resumes REA

Adds a joystick mode to run with NONE instead of KICK/PUNCH control

Changes default arm positions to raised elbows and neck to be angled down