0.8.18.39489 - New eye tracking "eye widen" expression and hidden sessions!

- Added new "Eye Widen" eye tracking parameter for Vive Pro Eye from the v2 tracking engine
-- This tracks how much the eye is widened. You can access it on the EyeManager and drive through LinearEyeDriver
- Added "Don't show in session lists" setting to the session dialog, which allows excluding the world from showing up in the session lists, regardless of its access level (requested by @Shifty)
-- If the world access level is set to Anyone, then anybody with a link/invite will be able to join (and anyone can invite anyone else)
- Added "Griping Body Node" to the locomotion grip events, which indicates which body node (usually LeftHand or RightHand) is gripping onto given object (requested by @Vigilabo)
- Added "Remove Alpha" texture processing option which completely removes the alpha channel
- Added "Is User Patron" LogiX node, which allows checking if given user is Patreon supporter (based on suggestion by @0utsider)


- Increased broadcast volume to normal to compensate the current audio spatializer
- Added a delay when opening world from a link and the engine is booting up, to prevent joining of private/friends-only sessions failing due to not being logged in yet (reported by @Shifty)