Start adding main menu

Conflicts:
	source/index.js

Conflicts:
	index.vwf.html
Added overlay
Play intro video after play game is clicked

Conflicts:
	source/index.js
Cleaned up render switching

Conflicts:
	source/index.js
Made main menu a scenario

Conflicts:
	index.vwf.yaml
Cleaned up code

Conflicts:
	index.vwf.html
Fixed version css
Fixed spacing in utils.js
Clear renderer on transition to RENDER_NONE
Removed introScreenController and modified transitions
Clean up transitions some
Center video
Addressed PR comments
Merge pull request #332 from virtual-world-framework/main-menu

Main menu