Scene view picking and more!

A bunch of changes gearing up for release:

• Clicking on raymarched objects in the Scene View window now selects them.
• GameObjects get renamed from the defaults "Sphere" and "Blend," etc. when you change their raymarching snippets.
  • Only happens if the names "match" and you don't have more than one object/material/blend on the GameObject.
• Removed beta object previews.
• Customize where generated shaders get placed in your project.
  • See the new "More Preferences..." button in the Raymarcher component to customize this.
• Added a new "Toggle" snippet input type for boolean values
• Cleaned up unused and broken snippets in the Examples/ folder.

Thanks to @thnewlands for lots of good feedback!