Prox sensor re-integration (#220)

* added arbitrary orientation change

* removed commented code

* updated to OVR 1.4.18

* changed two instances using new to init via array

* moved prox sensor action to haptic instead of Misc

* fixed json file, added prox sensor back for mic mute/un-mute

* added proximity sensor to audio and haptic chaperone warnings

* fixed fall-through behavior

* removed bad prox code

src/openvr/ivrinput.cpp

@@ -302,7 +302,7 @@ bool SteamIVRInput::chaperoneToggle()
 
 bool SteamIVRInput::proxState()
 {
-    return isDigitalActionActivatedConstant( m_pushToTalk );
+    return isDigitalActionActivatedConstant( m_proxSensor );
 }
 
 bool SteamIVRInput::keyboardOne()