Add VR display auto-calibration logic
Add VR display auto-calibration user message calculations
Make overlays accessible from C++ code
Add some property setters to the billboard overlay
Display a static billboard prompting user to hold still to calibrate HMD
Fix avatar rotation erroneously initiating HMD calibration
Delete calibration message if exit VR display while calibrating
Fix header declaration
Make calibration message update its location more often
Add gamepad.js
fix for delete of object table row
Update gamepad.js to work with wired 360 controller
remove some extra console logs
Add wired 360 controller on Windows support
Merge pull request #3578 from huffman/xbox-controller

Xbox controller script
remove xbox.js now that we have gamepad.js
Merge pull request #3577 from birarda/master

fix for delete of object table row
Update SVG file location
Use const parameters
Use NULL rather than 0 for "no overlay"