Add reality player feedback: headbob and footstep sound

[stefanofossati]

The feedbacks of the reality player are added:

• the headbob of the camera of the reality player
• the footstep sound feedback that is realated to the headbob movement

What is missing:

• a right audio track for the feedback when the reality player lends to the ground

[azazellus]

Works really really well!!