Fiddled with Controls.  Added 10 trees and random placing.  Added loading screen.
Added song and fiddled with landing page
Clean up outdated comments, no functionality change
Delete unused files and images
Clean up directory hierarchy
Delete unused function addSphereAtLocation
Use more semantic HTML to display player position
Make scene a global variable

This removes unnecessary complexity caused by premature generalization.
It is consistent with ground, and also allows callbacks that must have
zero arguments to modify the scene.
Merge branch 'cleanup'
getGroundHeight ray starts at MAX_HEIGHT_DISPLACEMENT+1
Trees appear when running locally

Previously, the code used an absolute path referring to a directory that
didn't exist in the repository. Be sure to NEVER use absolute paths so
we can continue to develop and test locally.
Trees are placed after scene is loaded

They no longer block the game from starting.
Still does not prevent tree from spawning 'on top' of the player.
Spawn at random point with minimum altitude

You no longer float downward to reach the ground.
This also makes gravity hacks unnecessary.
Merge branch 'tree-and-player-placement'