Adds new config options so the new rendeirng features can be used by the public, tweaks some of the default parameters and changes some of the elements in the UI Menu Config Video class.

* Adds "back light" by default to all light sources (adds more contrast to block sides which lie on the opposite side of the sun's or any other light source's position)
* Adds new local reflections (screen space reflections) as the new "not so costly" way to add reflections to water surfaces - adjusted the existing reflections button in the settings according to the new features
* Adds new environment effects settings button to the UI Menu Config Video class which replaces the existing "Animate Grass" button (environment effects include animated grass, animated water, volumetric fog and volumetric lighting)
* ... and thus enables volumetric lighting as a feature which can be enabled by setting the environment effects to high - this feature still needs a lot of tweaking until it looks right.
* Tweaks local reflections to fade out in areas that will most likely fail the ray marching because no reflection information is available on the screen
* Limits local reflections to ocean water surfaces for the time being
* Enabled animated grass by default for new users
* Tweaked water reflection and wave simulation settings