Re-Add color overlay (#311)

* fixed Chaperone toggle, toggle state on launch

* made update rates based on variable frame rate assuming 90 default

* added overlay color back in

* fixed opacity value not synching

* updated to ovr 1.8.19

* fixed license issue

* rolled back ovr update

* fixed overlay toggle state, formatting, and clamped max opacity to .85%

src/utils/FrameRateUtils.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <openvr.h>
+
+namespace utils
+{
+unsigned int adjustUpdateRate( const unsigned int keyvalue );
+
+} // end namespace utils